Patch Tuesday, Good Riddance 2020 Edition

Microsoft today issued its final batch of security updates for Windows PCs in 2020, ending the year with a relatively light patch load. Nine of the 58 security vulnerabilities addressed this month earned Microsoft’s most-dire “critical” label, meaning they can be abused by malware or miscreants to seize remote control over PCs without any help from users.

Mercifully, it does not appear that any of the flaws fixed this month are being actively exploited, nor have any them been detailed publicly prior to today.

The critical bits reside in updates for Microsoft Exchange Server, Sharepoint Server, and Windows 10 and Server 2016 systems. Additionally, Microsoft released an advisory on how to minimize the risk from a DNS spoofing weakness in Windows Server 2008 through 2019.

Some of the sub-critical “important” flaws addressed this month also probably deserve prompt patching in enterprise environments, including a trio of updates tackling security issues with Microsoft Office.

“Given the speed with which attackers often weaponize Microsoft Office vulnerabilities, these should be prioritized in patching,” said Allan Liska, senior security architect at Recorded Future. “The vulnerabilities, if exploited, would allow an attacker to execute arbitrary code on a victim’s machine. These vulnerabilities affect Microsoft Excel 2013 through 2019, Microsoft 365 32 and 64 bit versions, Microsoft Office 2019 32 and 64 bit versions, and Microsoft Excel for Mac 2019.”

We also learned this week that Redmond quietly addressed a scary “zero-click” vulnerability in its Microsoft Teams platform that would have let anyone execute code of their choosing just by sending the target a specially-crafted chat message to a Teams users. The bug was cross-platform, meaning it could also have been used to deliver malicious code to people using Teams on non-Windows devices.

Researcher Oskars Vegeris said in a proof-of-concept post to Github that he reported the flaw to Microsoft at the end of August, but that Microsoft didn’t assign the bug a Common Vulnerabilities and Exposure (CVE) rating because it has a policy of not doing so for bugs that can be fixed from Microsoft’s end without user interaction.

According to Vegeris, Microsoft addressed the Teams flaw at the end of October. But he said the bug they fixed was the first of five zero or one-click remote code execution flaws he has found and reported in Teams. Reached via LinkedIn, Vegeris declined to say whether Microsoft has yet addressed the remaining Teams issues.

Separately, Adobe issued security updates for its Prelude, Experience Manager and Lightroom software. There were no security updates for Adobe Flash Player, which is fitting considering Adobe is sunsetting the program at the end of the year. Microsoft is taking steps to remove Flash from its Windows browsers, and Google and Firefox already block Flash by default.

It’s a good idea for Windows users to get in the habit of updating at least once a month, but for regular users (read: not enterprises) it’s usually safe to wait a few days until after the patches are released, so that Microsoft has time to iron out any chinks in the new armor.

But before you update, please make sure you have backed up your system and/or important files. It’s not uncommon for a Windows update package to hose one’s system or prevent it from booting properly, and some updates have been known to erase or corrupt files.

So do yourself a favor and backup before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

And if you wish to ensure Windows has been set to pause updating so you can back up your files and/or system before the operating system decides to reboot and install patches on its own schedule, see this guide.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

Patch Tuesday, November 2020 Edition

Adobe and Microsoft each issued a bevy of updates today to plug critical security holes in their software. Microsoft’s release includes fixes for 112 separate flaws, including one zero-day vulnerability that is already being exploited to attack Windows users. Microsoft also is taking flak for changing its security advisories and limiting the amount of information disclosed about each bug.

Some 17 of the 112 issues fixed in today’s patch batch involve “critical” problems in Windows, or those that can be exploited by malware or malcontents to seize complete, remote control over a vulnerable Windows computer without any help from users.

Most of the rest were assigned the rating “important,” which in Redmond parlance refers to a vulnerability whose exploitation could “compromise the confidentiality, integrity, or availability of user data, or of the integrity or availability of processing resources.”

A chief concern among all these updates this month is CVE-2020-17087, which is an “important” bug in the Windows kernel that is already seeing active exploitation. CVE-2020-17087 is not listed as critical because it’s what’s known as a privilege escalation flaw that would allow an attacker who has already compromised a less powerful user account on a system to gain administrative control. In essence, it would have to be chained with another exploit.

Unfortunately, this is exactly what Google researchers described witnessing recently. On Oct. 20, Google released an update for its Chrome browser which fixed a bug (CVE-2020-15999) that was seen being used in conjunction with CVE-2020-17087 to compromise Windows users.

If you take a look at the advisory Microsoft released today for CVE-2020-17087 (or any others from today’s batch), you might notice they look a bit more sparse. That’s because Microsoft has opted to restructure those advisories around the Common Vulnerability Scoring System (CVSS) format to more closely align the format of the advisories with that of other major software vendors.

But in so doing, Microsoft has also removed some useful information, such as the description explaining in broad terms the scope of the vulnerability, how it can be exploited, and what the result of the exploitation might be. Microsoft explained its reasoning behind this shift in a blog post.

Not everyone is happy with the new format. Bob Huber, chief security officer at Tenable, praised Microsoft for adopting an industry standard, but said the company should consider that folks who review Patch Tuesday releases aren’t security practitioners but rather IT counterparts responsible for actually applying the updates who often aren’t able (and shouldn’t have to) decipher raw CVSS data.

“With this new format, end users are completely blind to how a particular CVE impacts them,” Huber said. “What’s more, this makes it nearly impossible to determine the urgency of a given patch. It’s difficult to understand the benefits to end-users. However, it’s not too difficult to see how this new format benefits bad actors. They’ll reverse engineer the patches and, by Microsoft not being explicit about vulnerability details, the advantage goes to attackers, not defenders. Without the proper context for these CVEs, it becomes increasingly difficult for defenders to prioritize their remediation efforts.”

Dustin Childs with Trend Micro‘s Zero Day Initiative also puzzled over the lack of details included in Microsoft advisories tied to two other flaws fixed today — including one in Microsoft Exchange Server (CVE-2020-16875) and CVE-2020-17051, which is a scary-looking weakness in the Windows Network File System (NFS).

The Exchange problem, Childs said, was reported by the winner of the Pwn2Own Miami bug finding contest.

“With no details provided by Microsoft, we can only assume this is the bypass of CVE-2020-16875 he had previously mentioned,” Childs said. “It is very likely he will publish the details of these bugs soon. Microsoft rates this as important, but I would treat it as critical, especially since people seem to find it hard to patch Exchange at all.”

Likewise, with CVE-2020-17051, there was a noticeable lack of detail for bug that earned a CVSS score of 9.8 (10 is the most dangerous).

“With no description to work from, we need to rely on the CVSS to provide clues about the real risk from the bug,” Childs said. “Consider this is listed as no user interaction with low attack complexity, and considering NFS is a network service, you should treat this as wormable until we learn otherwise.”

Separately, Adobe today released updates to plug at least 14 security holes in Adobe Acrobat and Reader. Details about those fixes are available here. There are no security updates for Adobe’s Flash Player, which Adobe has said will be retired at the end of the year. Microsoft, which has bundled versions of Flash with its Web browsers, says it plans to ship an update in December that will remove Flash from Windows PCs, and last month it made the removal tool available for download.

Windows 10 users should be aware that the operating system will download updates and install them on its own schedule, closing out active programs and rebooting the system. If you wish to ensure Windows has been set to pause updating so you can back up your files and/or system, see this guide.

But please do back up your system before applying any of these updates. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

Microsoft Patch Tuesday, October 2020 Edition

It’s Cybersecurity Awareness Month! In keeping with that theme, if you (ab)use Microsoft Windows computers you should be aware the company shipped a bevy of software updates today to fix at least 87 security problems in Windows and programs that run on top of the operating system. That means it’s once again time to backup and patch up.

Eleven of the vulnerabilities earned Microsoft’s most-dire “critical” rating, which means bad guys or malware could use them to gain complete control over an unpatched system with little or no help from users.

Worst in terms of outright scariness is probably CVE-2020-16898, which is a nasty bug in Windows 10 and Windows Server 2019 that could be abused to install malware just by sending a malformed packet of data at a vulnerable system. CVE-2020-16898 earned a CVSS Score of 9.8 (10 is the most awful).

Security vendor McAfee has dubbed the flaw “Bad Neighbor,” and in a blog post about it said a proof-of-concept exploit shared by Microsoft with its partners appears to be “both extremely simple and perfectly reliable,” noting that this sucker is imminently “wormable” — i.e. capable of being weaponized into a threat that spreads very quickly within networks.

“It results in an immediate BSOD (Blue Screen of Death), but more so, indicates the likelihood of exploitation for those who can manage to bypass Windows 10 and Windows Server 2019 mitigations,” McAfee’s Steve Povolny wrote. “The effects of an exploit that would grant remote code execution would be widespread and highly impactful, as this type of bug could be made wormable.”

Trend Micro’s Zero Day Initiative (ZDI) calls special attention to another critical bug quashed in this month’s patch batch: CVE-2020-16947, which is a problem with Microsoft Outlook that could result in malware being loaded onto a system just by previewing a malicious email in Outlook.

“The Preview Pane is an attack vector here, so you don’t even need to open the mail to be impacted,” said ZDI’s Dustin Childs.

While there don’t appear to be any zero-day flaws in October’s release from Microsoft, Todd Schell from Ivanti points out that a half-dozen of these flaws were publicly disclosed prior to today, meaning bad guys have had a jump start on being able to research and engineer working exploits.

Other patches released today tackle problems in Exchange Server, Visual Studio, .NET Framework, and a whole mess of other core Windows components.

For any of you who’ve been pining for a Flash Player patch from Adobe, your days of waiting are over. After several months of depriving us of Flash fixes, Adobe’s shipped an update that fixes a single — albeit critical — flaw in the program that crooks could use to install bad stuff on your computer just by getting you to visit a hacked or malicious website.

Chrome and Firefox both now disable Flash by default, and Chrome and IE/Edge auto-update the program when new security updates are available. Mercifully, Adobe is slated to retire Flash Player later this year, and Microsoft has said it plans to ship updates at the end of the year that will remove Flash from Windows machines.

It’s a good idea for Windows users to get in the habit of updating at least once a month, but for regular users (read: not enterprises) it’s usually safe to wait a few days until after the patches are released, so that Microsoft has time to iron out any chinks in the new armor.

But before you update, please make sure you have backed up your system and/or important files. It’s not uncommon for a Windows update package to hose one’s system or prevent it from booting properly, and some updates even have known to erase or corrupt files.

So do yourself a favor and backup before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

And if you wish to ensure Windows has been set to pause updating so you can back up your files and/or system before the operating system decides to reboot and install patches on its own schedule, see this guide.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

Microsoft Patch Tuesday, Sept. 2020 Edition

Microsoft today released updates to remedy nearly 130 security vulnerabilities in its Windows operating system and supported software. None of the flaws are known to be currently under active exploitation, but 23 of them could be exploited by malware or malcontents to seize complete control of Windows computers with little or no help from users.

The majority of the most dangerous or “critical” bugs deal with issues in Microsoft’s various Windows operating systems and its web browsers, Internet Explorer and Edge. September marks the seventh month in a row Microsoft has shipped fixes for more than 100 flaws in its products, and the fourth month in a row that it fixed more than 120.

Among the chief concerns for enterprises this month is CVE-2020-16875, which involves a critical flaw in the email software Microsoft Exchange Server 2016 and 2019. An attacker could leverage the Exchange bug to run code of his choosing just by sending a booby-trapped email to a vulnerable Exchange server.

“That doesn’t quite make it wormable, but it’s about the worst-case scenario for Exchange servers,” said Dustin Childs, of Trend Micro’s Zero Day Initiative. “We have seen the previously patched Exchange bug CVE-2020-0688 used in the wild, and that requires authentication. We’ll likely see this one in the wild soon. This should be your top priority.”

Also not great for companies to have around is CVE-2020-1210, which is a remote code execution flaw in supported versions of Microsoft Sharepoint document management software that bad guys could attack by uploading a file to a vulnerable Sharepoint site. Security firm Tenable notes that this bug is reminiscent of CVE-2019-0604, another Sharepoint problem that’s been exploited for cybercriminal gains since April 2019.

Microsoft fixed at least five other serious bugs in Sharepoint versions 2010 through 2019 that also could be used to compromise systems running this software. And because ransomware purveyors have a history of seizing upon Sharepoint flaws to wreak havoc inside enterprises, companies should definitely prioritize deployment of these fixes, says Alan Liska, senior security architect at Recorded Future.

Todd Schell at Ivanti reminds us that Patch Tuesday isn’t just about Windows updates: Google has shipped a critical update for its Chrome browser that resolves at least five security flaws that are rated high severity. If you use Chrome and notice an icon featuring a small upward-facing arrow inside of a circle to the right of the address bar, it’s time to update. Completely closing out Chrome and restarting it should apply the pending updates.

Once again, there are no security updates available today for Adobe’s Flash Player, although the company did ship a non-security software update for the browser plugin. The last time Flash got a security update was June 2020, which may suggest researchers and/or attackers have stopped looking for flaws in it. Adobe says it will retire the plugin at the end of this year, and Microsoft has said it plans to completely remove the program from all Microsoft browsers via Windows Update by then.

Before you update with this month’s patch batch, please make sure you have backed up your system and/or important files. It’s not uncommon for Windows updates to hose one’s system or prevent it from booting properly, and some updates even have known to erase or corrupt files.

So do yourself a favor and backup before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

And if you wish to ensure Windows has been set to pause updating so you can back up your files and/or system before the operating system decides to reboot and install patches on its own schedule, see this guide.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

Microsoft Put Off Fixing Zero Day for 2 Years

A security flaw in the way Microsoft Windows guards users against malicious files was actively exploited in malware attacks for two years before last week, when Microsoft finally issued a software update to correct the problem.

One of the 120 security holes Microsoft fixed on Aug. 11’s Patch Tuesday was CVE-2020-1464, a problem with the way every supported version of Windows validates digital signatures for computer programs.

Code signing is the method of using a certificate-based digital signature to sign executable files and scripts in order to verify the author’s identity and ensure that the code has not been changed or corrupted since it was signed by the author.

Microsoft said an attacker could use this “spoofing vulnerability” to bypass security features intended to prevent improperly signed files from being loaded. Microsoft’s advisory makes no mention of security researchers having told the company about the flaw, which Microsoft acknowledged was actively being exploited.

In fact, CVE-2020-1464 was first spotted in attacks used in the wild back in August 2018. And several researchers informed Microsoft about the weakness over the past 18 months.

Bernardo Quintero is the manager at VirusTotal, a service owned by Google that scans any submitted files against dozens of antivirus services and displays the results. On Jan. 15, 2019, Quintero published a blog post outlining how Windows keeps the Authenticode signature valid after appending any content to the end of Windows Installer files (those ending in .MSI) signed by any software developer.

Quintero said this weakness would particularly acute if an attacker were to use it to hide a malicious Java file (.jar). And, he said, this exact attack vector was indeed detected in a malware sample sent to VirusTotal.

“In short, an attacker can append a malicious JAR to a MSI file signed by a trusted software developer (like Microsoft Corporation, Google Inc. or any other well-known developer), and the resulting file can be renamed with the .jar extension and will have a valid signature according Microsoft Windows,” Quintero wrote.

But according to Quintero, while Microsoft’s security team validated his findings, the company chose not to address the problem at the time.

“Microsoft has decided that it will not be fixing this issue in the current versions of Windows and agreed we are able to blog about this case and our findings publicly,” his blog post concluded.

Tal Be’ery, founder of Zengo, and Peleg Hadar, senior security researcher at SafeBreach Labs, penned a blog post on Sunday that pointed to a file uploaded to VirusTotal in August 2018 that abused the spoofing weakness, which has been dubbed GlueBall. The last time that August 2018 file was scanned at VirusTotal (Aug 14, 2020), it was detected as a malicious Java trojan by 28 of 59 antivirus programs.

More recently, others would likewise call attention to malware that abused the security weakness, including this post in June 2020 from the Security-in-bits blog.

Image: Securityinbits.com

Be’ery said the way Microsoft has handled the vulnerability report seems rather strange.

“It was very clear to everyone involved, Microsoft included, that GlueBall is indeed a valid vulnerability exploited in the wild,” he wrote. “Therefore, it is not clear why it was only patched now and not two years ago.”

Asked to comment on why it waited two years to patch a flaw that was actively being exploited to compromise the security of Windows computers, Microsoft dodged the question, saying Windows users who have applied the latest security updates are protected from this attack.

“A security update was released in August,” Microsoft said in a written statement sent to KrebsOnSecurity. “Customers who apply the update, or have automatic updates enabled, will be protected. We continue to encourage customers to turn on automatic updates to help ensure they are protected.”

Update, 12:45 a.m. ET: Corrected attribution on the June 2020 blog article about GlueBall exploits in the wild.

Microsoft Patch Tuesday, August 2020 Edition

Microsoft today released updates to plug at least 120 security holes in its Windows operating systems and supported software, including two newly discovered vulnerabilities that are actively being exploited. Yes, good people of the Windows world, it’s time once again to backup and patch up!

At least 17 of the bugs squashed in August’s patch batch address vulnerabilities Microsoft rates as “critical,” meaning they can be exploited by miscreants or malware to gain complete, remote control over an affected system with little or no help from users. This is the sixth month in a row Microsoft has shipped fixes for more than 100 flaws in its products.

The most concerning of these appears to be CVE-2020-1380, which is a weaknesses in Internet Explorer that could result in system compromise just by browsing with IE to a hacked or malicious website. Microsoft’s advisory says this flaw is currently being exploited in active attacks.

The other flaw enjoying active exploitation is CVE-2020-1464, which is a “spoofing” bug in virtually supported version of Windows that allows an attacker to bypass Windows security features and load improperly signed files.

Trend Micro’s Zero Day Initiative points to another fix — CVE-2020-1472 — which involves a critical issue in Windows Server versions that could let an unauthenticated attacker gain administrative access to a Windows domain controller and run an application of their choosing. A domain controller is a server that responds to security authentication requests in a Windows environment, and a compromised domain controller can give attackers the keys to the kingdom inside a corporate network.

“It’s rare to see a Critical-rated elevation of privilege bug, but this one deserves it,” said ZDI’S Dustin Childs. “What’s worse is that there is not a full fix available.”

Perhaps the most “elite” vulnerability addressed this month earned the distinction of being named CVE-2020-1337, and refers to a security hole in the Windows Print Spooler service that could allow an attacker or malware to escalate their privileges on a system if they were already logged on as a regular (non-administrator) user.

Satnam Narang at Tenable notes that CVE-2020-1337 is a patch bypass for CVE-2020-1048, another Windows Print Spooler vulnerability that was patched in May 2020. Narang said researchers found that the patch for CVE-2020-1048 was incomplete and presented their findings for CVE-2020-1337 at the Black Hat security conference earlier this month. More information on CVE-2020-1337, including a video demonstration of a proof-of-concept exploit, is available here.

Adobe has graciously given us another month’s respite from patching Flash Player flaws, but it did release critical security updates for its Acrobat and PDF Reader products. More information on those updates is available here.

Keep in mind that while staying up-to-date on Windows patches is a must, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re less likely to pull your hair out when the odd buggy patch causes problems booting the system.

So do yourself a favor and backup your files before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

And as ever, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

‘Wormable’ Flaw Leads July Microsoft Patches

Microsoft today released updates to plug a whopping 123 security holes in Windows and related software, including fixes for a critical, “wormable” flaw in Windows Server versions that Microsoft says is likely to be exploited soon. While this particular weakness mainly affects enterprises, July’s care package from Redmond has a little something for everyone. So if you’re a Windows (ab)user, it’s time once again to back up and patch up (preferably in that order).

Top of the heap this month in terms of outright scariness is CVE-2020-1350, which concerns a remotely exploitable bug in more or less all versions of Windows Server that attackers could use to install malicious software simply by sending a specially crafted DNS request.

Microsoft said it is not aware of reports that anyone is exploiting the weakness (yet), but the flaw has been assigned a CVSS score of 10, which translates to “easy to attack” and “likely to be exploited.”

“We consider this to be a wormable vulnerability, meaning that it has the potential to spread via malware between vulnerable computers without user interaction,” Microsoft wrote in its documentation of CVE-2020-1350. “DNS is a foundational networking component and commonly installed on Domain Controllers, so a compromise could lead to significant service interruptions and the compromise of high level domain accounts.”

CVE-2020-1350 is just the latest worry for enterprise system administrators in charge of patching dangerous bugs in widely-used software. Over the past couple of weeks, fixes for flaws with high severity ratings have been released for a broad array of software products typically used by businesses, including Citrix, F5, Juniper, Oracle and SAP. This at a time when many organizations are already short-staffed and dealing with employees working remotely thanks to the COVID-19 pandemic.

The Windows Server isn’t the only nasty one addressed this month that malware or malcontents can use to break into systems without any help from users. A full 17 other critical flaws fixed in this release tackle security weaknesses that Microsoft assigned its most dire “critical” rating, such as in Office, Internet Exploder, SharePoint, Visual Studio, and Microsoft’s .NET Framework.

Some of the more eyebrow-raising critical bugs addressed this month include CVE-2020-1410, which according to Recorded Future concerns the Windows Address Book and could be exploited via a malicious vcard file. Then there’s CVE-2020-1421, which protects against potentially malicious .LNK files (think Stuxnet) that could be exploited via an infected removable drive or remote share. And we have the dynamic duo of CVE-2020-1435 and CVE-2020-1436, which involve problems with the way Windows handles images and fonts that could both be exploited to install malware just by getting a user to click a booby-trapped link or document.

Not to say flaws rated “important” as opposed to critical aren’t also a concern. Chief among those is CVE-2020-1463, a problem within Windows 10 and Server 2016 or later that was detailed publicly prior to this month’s Patch Tuesday.

Before you update with this month’s patch batch, please make sure you have backed up your system and/or important files. It’s not uncommon for a particular Windows update to hose one’s system or prevent it from booting properly, and some updates even have been known to erase or corrupt files. Last month’s bundle of joy from Microsoft sent my Windows 10 system into a perpetual crash state. Thankfully, I was able to restore from a recent backup.

So do yourself a favor and backup before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

Also, keep in mind that Windows 10 is set to apply patches on its own schedule, which means if you delay backing up you could be in for a wild ride. If you wish to ensure the operating system has been set to pause updating so you can back up your files and/or system before the operating system decides to reboot and install patches whenever it sees fit, see this guide.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips. Also, keep an eye on the AskWoody blog from Woody Leonhard, who keeps a reliable lookout for buggy Microsoft updates each month.

Microsoft Patch Tuesday, June 2020 Edition

Microsoft today released software patches to plug at least 129 security holes in its Windows operating systems and supported software, by some accounts a record number of fixes in one go for the software giant. None of the bugs addressed this month are known to have been exploited or detailed prior to today, but there are a few vulnerabilities that deserve special attention — particularly for enterprises and employees working remotely.

June marks the fourth month in a row that Microsoft has issued fixes to address more than 100 security flaws in its products. Eleven of the updates address problems Microsoft deems “critical,” meaning they could be exploited by malware or malcontents to seize complete, remote control over vulnerable systems without any help from users.

A chief concern among the panoply of patches is a trio of vulnerabilities in the Windows file-sharing technology (a.k.a. Microsoft Server Message Block or “SMB” service). Perhaps most troubling of these (CVE-2020-1301) is a remote code execution bug in SMB capabilities built into Windows 7 and Windows 2008 systems — both operating systems that Microsoft stopped supporting with security updates in January 2020. One mitigating factor with this flaw is that an attacker would need to be already authenticated on the network to exploit it, according to security experts at Tenable.

The SMB fixes follow closely on news that proof-of-concept code was published this week that would allow anyone to exploit a critical SMB flaw Microsoft patched for Windows 10 systems in March (CVE-2020-0796). Unlike this month’s critical SMB bugs, CVE-2020-0796 does not require the attacker to be authenticated to the target’s network. And with countless company employees now working remotely, Windows 10 users who have not yet applied updates from March or later could be dangerously exposed right now.

Microsoft Office and Excel get several updates this month. Two different flaws in Excel (CVE-2020-1225 and CVE-2020-1226) could be used to remotely commandeer a computer running Office just by getting a user to open a booby-trapped document. Another weakness (CVE-2020-1229) in most versions of Office may be exploited to bypass security features in Office simply by previewing a malicious document in the preview pane. This flaw also impacts Office for Mac, although updates are not yet available for that platform.

After months of giving us a welcome break from patching, Adobe has issued an update for its Flash Player program that fixes a single, albeit critical security problem. Adobe says it is not aware of any active exploits against the Flash flaw. Mercifully, Chrome and Firefox both now disable Flash by default, and Chrome and IE/Edge auto-update the program when new security updates are available. Adobe is slated to retire Flash Player later this year. Adobe also released security updates for its Experience Manager and Framemaker products.

Windows 7 users should be aware by now that while a fair number of flaws addressed this month by Microsoft affect Windows 7 systems, this operating system is no longer being supported with security updates (unless you’re an enterprise taking advantage of Microsoft’s paid extended security updates program, which is available to Windows 7 Professional and Windows 7 enterprise users).

Before you update with this month’s patch batch, please make sure you have backed up your system and/or important files. It’s not uncommon for a wonky Windows update to hose one’s system or prevent it from booting properly, and some updates even have known to erase or corrupt files. So do yourself a favor and backup before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

And if you wish to ensure Windows has been set to pause updating so you can back up your files and/or system before the operating system decides to reboot and install patches on its own schedule, see this guide.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

Further reading:

AskWoody and Martin Brinkmann on Patch Tuesday fixes and potential pitfalls

Trend Micro’s Zero Day Initiative June 2020 patch lowdown

U.S-CERT on Active Exploitation of CVE-2020-0796

Microsoft Patch Tuesday, May 2020 Edition

Microsoft today issued software updates to plug at least 111 security holes in Windows and Windows-based programs. None of the vulnerabilities were labeled as being publicly exploited or detailed prior to today, but as always if you’re running Windows on any of your machines it’s time once again to prepare to get your patches on.

May marks the third month in a row that Microsoft has pushed out fixes for more than 110 security flaws in its operating system and related software. At least 16 of the bugs are labeled “Critical,” meaning ne’er-do-wells can exploit them to install malware or seize remote control over vulnerable systems with little or no help from users.

But focusing solely on Microsoft’s severity ratings may obscure the seriousness of the flaws being addressed this month. Todd Schell, senior product manager at security vendor Ivanti, notes that if one looks at the “exploitability assessment” tied to each patch — i.e., how likely Microsoft considers each can and will be exploited for nefarious purposes — it makes sense to pay just as much attention to the vulnerabilities Microsoft has labeled with the lesser severity rating of “Important.”

Virtually all of the non-critical flaws in this month’s batch earned Microsoft’s “Important” rating.

“What is interesting and often overlooked is seven of the ten [fixes] at higher risk of exploit are only rated as Important,” Schell said. “It is not uncommon to look to the critical vulnerabilities as the most concerning, but many of the vulnerabilities that end up being exploited are rated as Important vs Critical.”

For example, Satnam Narang from Tenable notes that two remote code execution flaws in Microsoft Color Management (CVE-2020-1117) and Windows Media Foundation (CVE-2020-1126) could be exploited by tricking a user into opening a malicious email attachment or visiting a website that contains code designed to exploit the vulnerabilities. However, Microsoft rates these vulnerabilities as “Exploitation Less Likely,” according to their Exploitability Index.

In contrast, three elevation of privilege vulnerabilities that received a rating of “Exploitation More Likely” were also patched, Narang notes. These include a pair of “Important” flaws in Win32k (CVE-2020-1054, CVE-2020-1143) and one in the Windows Graphics Component (CVE-2020-1135). Elevation of Privilege vulnerabilities are used by attackers once they’ve managed to gain access to a system in order to execute code on their target systems with elevated privileges. There are at least 56 of these types of fixes in the May release.

Schell says if your organization’s plan for prioritizing the deployment of this month’s patches stops at vendor severity or even CVSS scores above a certain level you may want to reassess your metrics.

“Look to other risk metrics like Publicly Disclosed, Exploited (obviously), and Exploitability Assessment (Microsoft specific) to expand your prioritization process,” he advised.

As it usually does each month on Patch Tuesday, Adobe also has issued updates for some of its products. An update for Adobe Acrobat and Reader covers two dozen critical and important vulnerabilities. There are no security fixes for Adobe’s Flash Player in this month’s release.

Just a friendly reminder that while many of the vulnerabilities fixed in today’s Microsoft patch batch affect Windows 7 operating systems — including all three of the zero-day flaws — this OS is no longer being supported with security updates (unless you’re an enterprise taking advantage of Microsoft’s paid extended security updates program, which is available to Windows 7 Professional and Windows 7 enterprise users).

If you rely on Windows 7 for day-to-day use, it’s time to think about upgrading to something newer. That something might be a PC with Windows 10. Or maybe you have always wanted that shiny MacOS computer.

If cost is a primary motivator and the user you have in mind doesn’t do much with the system other than browsing the Web, perhaps a Chromebook or an older machine with a recent version of Linux is the answer (Ubuntu may be easiest for non-Linux natives). Whichever system you choose, it’s important to pick one that fits the owner’s needs and provides security updates on an ongoing basis.

Keep in mind that while staying up-to-date on Windows patches is a must, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re not losing your mind when the odd buggy patch causes problems booting the system.

So backup your files before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

And if you wish to ensure Windows has been set to pause updating so you can back up your files and/or system before the operating system decides to reboot and install patches on its own schedule, see this guide.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips. Also, keep an eye on the AskWoody blog from Woody Leonhard, who keeps a reliable lookout for buggy Microsoft updates each month.

Further reading:

SANS Internet Storm Center breakdown by vulnerability and severity

Microsoft’s Security Update catalog

BleepingComputer on May 2020 Patch Tuesday

Microsoft Patch Tuesday, April 2020 Edition

Microsoft today released updates to fix 113 security vulnerabilities in its various Windows operating systems and related software. Those include at least three flaws that are actively being exploited, as well as two others which were publicly detailed prior to today, potentially giving attackers a head start in figuring out how to exploit the bugs.

Nineteen of the weaknesses fixed on this Patch Tuesday were assigned Microsoft’s most-dire “critical” rating, meaning malware or miscreants could exploit them to gain complete, remote control over vulnerable computers without any help from users.

Near the top of the heap is CVE-2020-1020, a remotely exploitable bug in the Adobe Font Manager library that was first detailed in late March when Microsoft said it had seen the flaw being used in active attacks.

The Adobe Font Manager library is the source of yet another zero-day flaw — CVE-2020-0938 — although experts at security vendor Tenable say there is currently no confirmation that the two are related to the same set of in-the-wild attacks. Both flaws could be exploited by getting a Windows users to open a booby-trapped document or viewing one in the Windows Preview Pane.

The other zero-day flaw (CVE-2020-1027) affects Windows 7 and Windows 10 systems, and earned a slightly less dire “important” rating from Microsoft because it’s an “elevation of privilege” bug that requires the attacker to be locally authenticated.

Many security news sites are reporting that Microsoft addressed a total of four zero-day flaws this month, but it appears the advisory for a critical Internet Explorer flaw (CVE-2020-0968) has been revised to indicate Microsoft has not yet received reports of it being used in active attacks. However, the advisory says this IE bug is likely to be exploited soon.

Researchers at security firm Recorded Future zeroed in on CVE-2020-0796, a critical vulnerability dubbed “SMBGhost” that was rumored to exist in last month’s Patch Tuesday but for which an out-of-band patch wasn’t released until March 12. The problem resides in a file-sharing component of Windows, and could be exploited merely by sending the victim machine specially-crafted data packets. Proof-of-concept code showing how to exploit the bug was released April 1, but so far there are no indications this method has been incorporated into malware or active attacks.

Recorded Future’s Allan Liska notes that one reason these past few months have seen so many patches from Microsoft is the company recently hired “SandboxEscaper,” a nickname used by the security researcher responsible for releasing more than a half-dozen zero-day flaws against Microsoft products last year.

“SandboxEscaper has made several contributions to this month’s Patch Tuesday,” Liska said. “This is great news for Microsoft and the security community at large.”

Once again, Adobe has blessed us with a respite from updating its Flash Player program with security fixes. I look forward to the end of this year, when the company has promised to sunset this buggy and insecure program once and for all. Adobe did release security updates for its ColdFusion, After Effects and Digital Editions software.

Speaking of buggy software platforms, Oracle has released a quarterly patch update to fix more than 400 security flaws across multiple products, including its Java SE program. If you’ve got Java installed and you need/want to keep it installed, please make sure it’s up-to-date.

Now for my obligatory disclaimers. Just a friendly reminder that while many of the vulnerabilities fixed in today’s Microsoft patch batch affect Windows 7 operating systems — including all three of the zero-day flaws — this OS is no longer being supported with security updates (unless you’re an enterprise taking advantage of Microsoft’s paid extended security updates program, which is available to Windows 7 Professional and Windows 7 enterprise users).

If you rely on Windows 7 for day-to-day use, it’s to think about upgrading to something newer. That something might be a computer with Windows 10. Or maybe you have always wanted that shiny MacOS computer.

If cost is a primary motivator and the user you have in mind doesn’t do much with the system other than browsing the Web, perhaps a Chromebook or an older machine with a recent version of Linux is the answer (Ubuntu may be easiest for non-Linux natives). Whichever system you choose, it’s important to pick one that fits the owner’s needs and provides security updates on an ongoing basis.

Keep in mind that while staying up-to-date on Windows patches is a must, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re not losing your mind when the odd buggy patch causes problems booting the system.

So do yourself a favor and backup your files before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips. Also, keep an eye on the AskWoody blog from Woody Leonhard, who keeps a close eye on buggy Microsoft updates each month.

Further reading:

Qualys breakdown on April 2020 Patch Tuesday

SANS Internet Storm Center on Patch Tuesday

‘War Dialing’ Tool Exposes Zoom’s Password Problems

As the Coronavirus pandemic continues to force people to work from home, countless companies are now holding daily meetings using videoconferencing services from Zoom. But without the protection of a password, there’s a decent chance your next Zoom meeting could be “Zoom bombed” — attended or disrupted by someone who doesn’t belong. And according to data gathered by a new automated Zoom meeting discovery tool dubbed “zWarDial,” a crazy number of meetings at major corporations are not being protected by a password.

zWarDial, an automated tool for finding non-password protected Zoom meetings. According to its makers, zWarDial can find on average 110 meetings per hour, and has a success rate of around 14 percent.

Each Zoom conference call is assigned a Meeting ID that consists of 9 to 11 digits. Naturally, hackers have figured out they can simply guess or automate the guessing of random IDs within that space of digits.

Security experts at Check Point Research did exactly that last summer, and found they were able to predict approximately four percent of randomly generated Meeting IDs. The Check Point researchers said enabling passwords on each meeting was the only thing that prevented them from randomly finding a meeting.

Zoom responded by saying it was enabling passwords by default in all future scheduled meetings. Zoom also said it would block repeated attempts to scan for meeting IDs, and that it would no longer automatically indicate if a meeting ID was valid or invalid.

Nevertheless, the incidence of Zoombombing has skyrocketed over the past few weeks, even prompting an alert by the FBI on how to secure meetings against eavesdroppers and mischief-makers. This suggests that many Zoom users have disabled passwords by default and/or that Zoom’s new security feature simply isn’t working as intended for all users.

New data and acknowledgments by Zoom itself suggest the latter may be more likely.

Earlier this week, KrebsOnSecurity heard from Trent Lo, a security professional and co-founder of SecKC, Kansas City’s longest-running monthly security meetup. Lo and fellow SecKC members recently created zWarDial, which borrows part of its name from the old phone-based war dialing programs that called random or sequential numbers in a given telephone number prefix to search for computer modems.

Lo said zWarDial evades Zoom’s attempts to block automated meeting scans by routing the searches through multiple proxies in Tor, a free and open-source software that lets users browse the Web anonymously.

“Zoom recently said they fixed this but I’m using a totally different URL and passing a cookie along with that URL,” Lo said, describing part of how the tool works on the back end. “This gives me the [Zoom meeting] room information without having to log in.”

Lo said a single instance of zWarDial can find approximately 100 meetings per hour, but that multiple instances of the tool running in parallel could probably discover most of the open Zoom meetings on any given day. Each instance, he said, has a success rate of approximately 14 percent, meaning for each random meeting number it tries, the program has a 14 percent chance of finding an open meeting.

Only meetings that are protected by a password are undetectable by zWarDial, Lo said.

“Having a password enabled on the meeting is the only thing that defeats it,” he said.

Lo shared the output of one day’s worth of zWarDial scanning, which revealed information about nearly 2,400 upcoming or recurring Zoom meetings. That information included the link needed to join each meeting; the date and time of the meeting; the name of the meeting organizer; and any information supplied by the meeting organizer about the topic of the meeting.

The results were staggering, and revealed details about Zoom meetings scheduled by some of the world’s largest companies, including major banks, international consulting firms, ride-hailing services, government contractors, and investment ratings firms.

KrebsOnSecurity is not naming the companies involved, but was able to verify dozens of them by matching the name of the meeting organizer with corporate profiles on LinkedIn.

By far the largest group of companies exposing their Zoom meetings are in the technology sector, and include a number of security and cloud technology vendors. These include at least one tech company that’s taken to social media warning people about the need to password protect Zoom meetings!

The distribution of Zoom meetings found by zWarDial, indexed by industry. As depicted above, zWarDial found roughly 2,400 exposed meetings in less than 24 hours. Image: SecKC.

A GREMLIN IN THE DEFAULTS?

Given the preponderance of Zoom meetings exposed by security and technology companies that ostensibly should know better, KrebsOnSecurity asked Zoom whether its approach of adding passwords by default to all new meetings was actually working as intended.

In reply, Zoom said it was investigating the possibility that its password-by-default approach may fail under certain circumstances.

“Zoom strongly encourages users to implement passwords for all of their meetings to ensure uninvited users are not able to join,” the company said in a written statement shared with this author.

“Passwords for new meetings have been enabled by default since late last year, unless account owners or admins opted out,” the statement continues. “We are looking into unique edge cases to determine whether, under certain circumstances, users unaffiliated with an account owner or administrator may not have had passwords switched on by default at the time that change was made.

The acknowledgment comes amid a series of security and privacy stumbles for Zoom, which has seen its user base grow exponentially in recent weeks. Zoom founder and chief executive Eric Yuan said in a recent blog post that the maximum number of daily meeting participants — both paid and free — has grown from around 10 million in December to 200 million in March.

That rapid growth has also brought additional scrutiny from security and privacy experts, who’ve found plenty of real and potential problems with the service of late. TechCrunch’s Zack Whittaker has a fairly comprehensive breakdown of them here; not included in that list is a story he broke earlier this week on a pair of zero-day vulnerabilities in Zoom that were publicly detailed by a former NSA expert.

Zoom CEO Yuan acknowledged that his company has struggled to keep up with steeply growing demand for its service and with the additional scrutiny that comes with it, saying in a blog post that for the next 90 days all new feature development was being frozen so the company’s engineers could focus on security issues.

Dave Kennedy, a security expert and founder of the security consultancy TrustedSec, penned a lengthy thread on Twitter saying while Zoom certainly has had its share of security and privacy goofs, some in the security community are unnecessarily exacerbating an already tough situation for Zoom and the tens of millions of users who rely on it for day-to-day meetings.

“What we have here is a company that is relatively easy to use for the masses (comes with its challenges on personal meeting IDs) and is relatively secure,” Kennedy wrote. “Yet the industry is making it out to be ‘this is malware’ and you can’t use this. This is extreme. We need to look at the risk specific applications pose and help voice a message of how people can leverage technology and be safe. Dropping zero-days to the media hurts our credibility, sensationalizes fear, and hurts others.”

“If there are ways for a company to improve, we should notify them and if they don’t fix their issues, we should call them out,” he continued. “We should not be putting fear into everyone, and leveraging the media as a method to create that fear.”

Zoom’s advice on securing meetings is here. SecKC’s Lo said organizations using Zoom should avoid posting the Zoom meeting links on social media, and always require a meeting password when possible.

“This should be enabled by default as a new customer or a trial user,” he said. “Legacy organizations will need to check their administration settings to make sure this is enabled. You can also enable ‘Embed password in meeting link for one-click join.’ This prevents an actor from accessing your meeting without losing the usability of sharing a link to join.”

In addition, Zoom users can disable “Allow participants to join the meeting before the host arrives.”

“If you have to have this feature enabled at least enable “notify host when participants join the meeting before them,” Lo advised. “This will notify you that someone might be using your meeting without your knowledge. If you must keep your meeting unprotected you should enable ‘Mask phone number in the participant list.’ Using the waiting list feature will prevent unwanted participants from accessing your meeting but it will still expose your meeting details if used without a password.”

Some of the security settings available to Zoom users. These and others can be found at https://www.zoom.us/profile/settings/

Zyxel Flaw Powers New Mirai IoT Botnet Strain

In February, hardware maker Zyxel fixed a zero-day vulnerability in its routers and VPN firewall products after KrebsOnSecurity told the company the flaw was being abused by attackers to break into devices. This week, security researchers said they spotted that same vulnerability being exploited by a new variant of Mirai, a malware strain that targets vulnerable Internet of Things (IoT) devices for use in large-scale attacks and as proxies for other cybercrime activity.

Security experts at Palo Alto Networks said Thursday their sensors detected the new Mirai variant — dubbed Mukashi — on Mar. 12. The new Mirai strain targets CVE-2020-9054, a critical flaw that exists in many VPN firewalls and network attached storage (NAS) devices made by Taiwanese vendor Zyxel Communication Corp., which boasts some 100 million devices deployed worldwide.

Like other Mirai variants, Mukashi constantly scans the Internet for vulnerable IoT devices like security cameras and digital video recorders (DVRs), looking for a range of machines protected only by factory-default credentials or commonly-picked passwords.

Palo Alto said IoT systems infected by Mukashi then report back to a control server, which can be used to disseminate new instructions — such as downloading additional software or launching distributed denial of service (DDoS) attacks.

The commands Mukashi botmasters can send to infected devices include scanning for and exploiting other systems, and launching DDoS attacks. Image: Palo Alto Networks.

Zyxel issued a patch for the flaw on Feb. 24, but the update did not fix the problem on many older Zyxel devices which are no longer being supported by the company. For those devices, Zyxel’s advice was not to leave them connected to the Internet.

A joint advisory on CVE-2020-9054 from the U.S. Department of Homeland Security and the CERT Coordination Center rates this vulnerability at a “10” — the most severe kind of flaw. The DHS/CERT advisory also includes sample code to test if a Zyxel product is vulnerable to the flaw.

My advice? If you can’t patch it, pitch it, as Mukashi is not the only thing interested in this Zyxel bug: Recent activity suggests attackers known for deploying ransomware have been actively working to test it for use against targets.

Microsoft Patch Tuesday, March 2020 Edition

Microsoft Corp. today released updates to plug more than 100 security holes in its various Windows operating systems and associated software. If you (ab)use Windows, please take a moment to read this post, backup your system(s), and patch your PCs.

All told, this patch batch addresses at least 115 security flaws. Twenty-six of those earned Microsoft’s most-dire “critical” rating, meaning malware or miscreants could exploit them to gain complete, remote control over vulnerable computers without any help from users.

Given the sheer number of fixes, mercifully there are no zero-day bugs to address, nor were any of them detailed publicly prior to today. Also, there were no security patches released by Adobe today. But there are a few eyebrow-raising Windows vulnerabilities worthy of attention.

Recorded Future warns exploit code is now available for one of the critical bugs Redmond patched last month in Microsoft Exchange (CVE-2020-0688), and that nation state actors have been observed abusing the exploit for targeted attacks.

One flaw fixed this month in Microsoft Word (CVE-2020-0852) could be exploited to execute malicious code on a Windows system just by getting the user to load an email containing a booby-trapped document in the Microsoft Outlook preview pane. CVE-2020-0852 is one just four remote execution flaws Microsoft patched this month in versions of Word.

One somewhat ironic weakness fixed today (CVE-2020-0872) resides in a new component Microsoft debuted this year called Application Inspector, a source code analyzer designed to help Windows developers identify “interesting” or risky features in open source software (such as the use of cryptography, connections made to a remote entity, etc).

Microsoft said this flaw can be exploited if a user runs Application Inspector on a hacked or booby-trapped program. Whoops. Animesh Jain from security vendor Qualys says this patch should be prioritized, despite being labeled as less severe (“important” versus “critical”) by Microsoft.

For enterprises, Qualys recommends prioritizing the patching of desktop endpoints over servers this month, noting that most of the other critical bugs patched today are prevalent on workstation-type devices. Those include a number of flaws that can be exploited simply by convincing a Windows user to browse to a malicious or hacked Web site.

While many of the vulnerabilities fixed in today’s patch batch affect Windows 7 operating systems, this OS is no longer being supported with security updates (unless you’re an enterprise taking advantage of Microsoft’s paid extended security updates program, which is available to Windows 7 Professional and Windows 7 enterprise users).

If you rely on Windows 7 for day-to-day use, it’s probably time to think about upgrading to something newer. That might be a computer with Windows 10. Or maybe you have always wanted that shiny MacOS computer.

If cost is a primary motivator and the user you have in mind doesn’t do much with the system other than browsing the Web, perhaps a Chromebook or an older machine with a recent version of Linux is the answer (Ubuntu may be easiest for non-Linux natives). Whichever system you choose, it’s important to pick one that fits the owner’s needs and provides security updates on an ongoing basis.

Keep in mind that while staying up-to-date on Windows patches is a must, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re not losing your mind when the odd buggy patch causes problems booting the system.

So do yourself a favor and backup your files before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips. Also, keep an eye on the AskWoody blog from Woody Leonhard, who keeps a close eye on buggy Microsoft updates each month.

Update, 7:50 p.m.: Microsoft has released an advisory about a remote code execution vulnerability in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests. Critical SMB (Windows file-sharing) flaws are dangerous because they are typically “wormable,” in that they can spread rapidly to vulnerable systems across an internal network with little to no human interaction.

“To exploit the vulnerability against an SMB Server, an unauthenticated attacker could send a specially crafted packet to a targeted SMBv3 Server,” Microsoft warned. “To exploit the vulnerability against an SMB Client, an unauthenticated attacker would need to configure a malicious SMBv3 Server and convince a user to connect to it.”

Microsoft’s advisory says the flaw is neither publicly disclosed nor exploited at the moment. It includes a workaround to mitigate the flaw in file-sharing servers, but says the workaround does not prevent the exploitation of clients.

Zyxel 0day Affects its Firewall Products, Too

On Monday, networking hardware maker Zyxel released security updates to plug a critical security hole in its network attached storage (NAS) devices that is being actively exploited by crooks who specialize in deploying ransomware. Today, Zyxel acknowledged the same flaw is present in many of its firewall products.

This week’s story on the Zyxel patch was prompted by the discovery that exploit code for attacking the flaw was being sold in the cybercrime underground for $20,000. Alex Holden, the security expert who first spotted the code for sale, said at the time the vulnerability was so “stupid” and easy to exploit that he wouldn’t be surprised to find other Zyxel products were similarly affected.

Now it appears Holden’s hunch was dead-on.

“We’ve now completed the investigation of all Zyxel products and found that firewall products running specific firmware versions are also vulnerable,” Zyxel wrote in an email to KrebsOnSecurity. “Hotfixes have been released immediately, and the standard firmware patches will be released in March.”

The updated security advisory from Zyxel states the exploit works against its UTM, ATP, and VPN firewalls running firmware version ZLD V4.35 Patch 0 through ZLD V4.35 Patch 2, and that those with firmware versions before ZLD V4.35 Patch 0 are not affected.

Zyxel’s new advisory suggests that some affected firewall product won’t be getting hotfixes or patches for this flaw, noting that the affected products listed in the advisory are only those which are “within their warranty support period.”

Indeed, while the exploit also works against more than a dozen of Zyxel’s NAS product lines, the company only released updates for NAS products that were newer than 2016. Its advice for those still using those unsupported NAS devices? “Do not leave the product directly exposed to the internet. If possible, connect it to a security router or firewall for additional protection.”

Hopefully, your vulnerable, unsupported Zyxel NAS isn’t being protected by a vulnerable, unsupported Zyxel firewall product.

CERT’s advisory on the flaw rate this vulnerability at a “10” — its most severe. My advice? If you can’t patch it, pitch it. The zero-day sales thread first flagged by Holden also hinted at the presence of post-authentication exploits in many Zyxel products, but the company did not address those claims in its security advisories.

Recent activity suggests that attackers known for deploying ransomware have been actively working to test the zero-day for use against targets. Holden said the exploit is now being used by a group of bad guys who are seeking to fold the exploit into Emotet, a powerful malware tool typically disseminated via spam that is frequently used to seed a target with malcode which holds the victim’s files for ransom.

“To me, a 0day exploit in Zyxel is not as scary as who bought it,” he said. “The Emotet guys have been historically targeting PCs, laptops and servers, but their venture now into IoT devices is very disturbing.”

Zyxel Fixes 0day in Network Storage Devices

Patch comes amid active exploitation by ransomware gangs

Networking hardware vendor Zyxel today released an update to fix a critical flaw in many of its network attached storage (NAS) devices that can be used to remotely commandeer them. The patch comes 12 days after KrebsOnSecurity alerted the company that precise instructions for exploiting the vulnerability were being sold for $20,000 in the cybercrime underground.

Based in Taiwan, Zyxel Communications Corp. (a.k.a “ZyXEL”) is a maker of networking devices, including Wi-Fi routers, NAS products and hardware firewalls. The company has roughly 1,500 employees and boasts some 100 million devices deployed worldwide. While in many respects the class of vulnerability addressed in this story is depressingly common among Internet of Things (IoT) devices, the flaw is notable because it has attracted the interest of groups specializing in deploying ransomware at scale.

KrebsOnSecurity first learned about the flaw on Feb. 12 from Alex Holden, founder of Milwaukee-based security firm Hold Security. Holden had obtained a copy of the exploit code, which allows an attacker to remotely compromise more than a dozen types of Zyxel NAS products remotely without any help from users.

A snippet from the documentation provided by 500mhz for the Zyxel 0day.

Holden said the seller of the exploit code — a ne’er-do-well who goes by the nickname “500mhz” –is known for being reliable and thorough in his sales of 0day exploits (a.k.a. “zero-days,” these are vulnerabilities in hardware or software products that vendors first learn about when exploit code and/or active exploitation shows up online).

For example, this and previous zero-days for sale by 500mhz came with exhaustive documentation detailing virtually everything about the flaw, including any preconditions needed to exploit it, step-by-step configuration instructions, tips on how to remove traces of exploitation, and example search links that could be used to readily locate thousands of vulnerable devices.

500mhz’s profile on one cybercrime forum states that he is constantly buying, selling and trading various 0day vulnerabilities.

“In some cases, it is possible to exchange your 0day with my existing 0day, or sell mine,” his Russian-language profile reads.

The profile page of 500mhz, translated from Russian to English via Google Chrome.

PARTIAL PATCH

KrebsOnSecurity first contacted Zyxel on Feb. 12, sharing a copy of the exploit code and description of the vulnerability. When four days elapsed without any response from the vendor to notifications sent via multiple methods, this author shared the same information with vulnerability analysts at the U.S. Department of Homeland Security (DHS) and with the CERT Coordination Center (CERT/CC), a partnership between DHS and Carnegie Mellon University.

Less than 24 hours after contacting DHS and CERT/CC, KrebsOnSecurity heard back from Zyxel, which thanked KrebsOnSecurity for the alert without acknowledging its failure to respond until they were sent the same information by others.

“Thanks for flagging,” Zyxel’s team wrote on Feb. 17. “We’ve just received an alert of the same vulnerabilities from US-CERT over the weekend, and we’re now in the process of investigating. Still, we heartily appreciate you bringing it to our attention.”

Earlier today, Zyxel sent a message saying it had published a security advisory and patch for the zero-day exploit in some of its affected products. The vulnerable devices include NAS542, NAS540, NAS520, NAS326, NSA325 v2, NSA325, NSA320S, NSA320, NSA310S, NSA310, NSA221, NSA220+, NSA220, and NSA210. The flaw is designated as CVE-2020-9054.

However, many of these devices are no longer supported by Zyxel and will not be patched. Zyxel’s advice for those users is simply “do not leave the product directly exposed to the internet.”

“If possible, connect it to a security router or firewall for additional protection,” the advisory reads.

Holden said given the simplicity of the exploit — which allows an attacker to seize remote control over an affected device by injecting just two characters to the username field of the login panel for Zyxel NAS devices — it’s likely other Zyxel products may have related vulnerabilities.

“Considering how stupid this exploit is, I’m guessing this is not the only one of its class in their products,” he said.

CERT’s advisory on the flaw rates it at a “10” — its most severe. The advisory includes additional mitigation instructions, including a proof-of-concept exploit that has the ability to power down affected Zyxel devices.

EMOTET GOES IOT?

Holden said recent activity suggests that attackers known for deploying ransomware have been actively working to test the zero-day for use against targets. Specifically, Holden said the exploit is now being used by a group of bad guys who are seeking to fold the exploit into Emotet, a powerful malware tool typically disseminated via spam that is frequently used to seed a target with malcode which holds the victim’s files for ransom.

Holden said 500mhz was offering the Zyxel exploit for $20,000 on cybercrime forums, although it’s not clear whether the Emotet gang paid anywhere near that amount for access to the code. Still, he said, ransomware gangs could easily earn back their investment by successfully compromising a single target with this simple but highly reliable exploit.

“From the attacker’s standpoint simple is better,” he said. “The commercial value of this exploit was set at $20,000, but that’s not much when you consider a ransomware gang could easily make that money back and then some in a short period of time.”

Emotet’s nascent forays into IoT come amid other disturbing developments for the prolific exploitation platform. Earlier this month, security researchers noted that Emotet now has the capability to spread in a worm-like fashion via Wi-Fi networks.

“To me, a 0day exploit in Zyxel is not as scary as who bought it,” he said. “The Emotet guys have been historically targeting PCs, laptops and servers, but their venture now into IoT devices is very disturbing.”

DISCLOSURE DEBATE

This experience was a good reminder that vulnerability reporting and remediation often can be a frustrating process. Twelve days turnaround is fairly quick as these things go, although probably not quick enough for customers using products affected by zero-day vulnerabilities.

It can be tempting when one is not getting any response from a vendor to simply publish an alert detailing one’s findings, and the pressure to do so certainly increases when there is a zero-day flaw involved. KrebsOnSecurity ultimately opted not to do that for three reasons.

Firstly, at the time there was no evidence that the flaws were being actively exploited, and because the vendor had assured DHS and CERT-CC that it would soon have a patch available.

Perhaps most importantly, public disclosure of an unpatched flaw could well have made a bad situation worse, without offering affected users much in the way of information about how to protect their systems.

Many hardware and software vendors include a link from their home pages to /security.txt, which is a proposed standard for allowing security researchers to quickly identify the points of contact at vendors when seeking to report security vulnerabilities. But even vendors who haven’t yet adopted this standard (Zyxel has not) usually will respond to reports at [email protected][vendordomainhere]; indeed, Zyxel encourages researchers to forward any such reports to [email protected]

On the subject of full disclosure, I should note that while this author is listed by Hold Security’s site as an advisor, KrebsOnSecurity has never sought nor received remuneration of any kind in connection with this role.

Microsoft Patch Tuesday, February 2020 Edition

Microsoft today released updates to plug nearly 100 security holes in various versions of its Windows operating system and related software, including a zero-day vulnerability in Internet Explorer (IE) that is actively being exploited. Also, Adobe has issued a bevy of security updates for its various products, including Flash Player and Adobe Reader/Acrobat.

A dozen of the vulnerabilities Microsoft patched today are rated “critical,” meaning malware or miscreants could exploit them remotely to gain complete control over an affected system with little to no help from the user.

Last month, Microsoft released an advisory warning that attackers were exploiting a previously unknown flaw in IE. That vulnerability, assigned as CVE-2020-0674, has been patched with this month’s release. It could be used to install malware just by getting a user to browse to a malicious or hacked Web site.

Microsoft once again fixed a critical flaw in the way Windows handles shortcut (.lnk) files (CVE-2020-0729) that affects Windows 8 and 10 systems, as well as Windows Server 2008-2012. Allan Liska, intelligence analyst at Recorded Future, says Microsoft considers exploitation of the vulnerability unlikely, but that a similar vulnerability discovered last year, CVE-2019-1280, was being actively exploited by the Astaroth trojan as recently as September.

Another flaw fixed this month in Microsoft Exchange 2010 through 2019 may merit special attention. The bug could allow attackers to exploit the Exchange Server and execute arbitrary code just by sending a specially crafted email. This vulnerability (CVE-2020-0688) is rated “important” rather than “critical,” but Liska says it seems potentially dangerous, as Microsoft identifies this as a vulnerability that is likely to be exploited.

In addition, Redmond addressed a critical issue (CVE-2020-0618) in the way Microsoft SQL Server versions 2012-2016 handle page requests.

After a several-month respite from patches for its Flash Player browser plug-in, Adobe has once again blessed us with a security update for this program (fixes one critical flaw). Thankfully, Chrome and Firefox both now disable Flash by default, and Chrome and IE/Edge auto-update the program when new security updates are available. Adobe is slated to retire Flash Player later this year.

Other Adobe products for which the company shipped updates today include Experience Manager, Digital Editions, Framemaker and Acrobat/Reader (17 flaws). Security experts at Qualys note that on January 28th, Adobe also issued an out-of-band patch for Magento, labeled as Priority 2.

“While none of the vulnerabilities disclosed in Adobe’s release are known to be Actively Attacked today, all patches should be prioritized on systems with these products installed,” said Qualys’s Jimmy Graham.

Windows 7 users should be aware by now that while a fair number of flaws addressed this month by Microsoft affect Windows 7 systems, this operating system is no longer being supported with security updates (unless you’re an enterprise taking advantage of Microsoft’s paid extended security updates program, which is available to Windows 7 Professional and Windows 7 enterprise users).

If you rely on Windows 7 for day-to-day use, it’s probably time to think about upgrading to something newer. That might be a computer with Windows 10. Or maybe you have always wanted that shiny MacOS computer.

If cost is a primary motivator and the user you have in mind doesn’t do much with the system other than browsing the Web, perhaps a Chromebook or an older machine with a recent version of Linux is the answer (Ubuntu may be easiest for non-Linux natives). Whichever system you choose, it’s important to pick one that fits the owner’s needs and provides security updates on an ongoing basis.

Keep in mind that while staying up-to-date on Windows patches is a must, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re not losing your mind when the odd buggy patch causes problems booting the system.

So do yourself a favor and backup your files before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips. Also, keep an eye on the AskWoody blog from Woody Leonhard, who keeps a close eye on buggy Microsoft updates each month.

Apple Addresses iPhone 11 Location Privacy Concern

Apple is rolling out a new update to its iOS operating system that addresses the location privacy issue on iPhone 11 devices that was first detailed here last month.

Beta versions of iOS 13.3.1 include a new setting that lets users disable the “Ultra Wideband” feature, a short-range technology that lets iPhone 11 users share files locally with other nearby phones that support this feature.

In December, KrebsOnSecurity pointed out the new iPhone 11 line queries the user’s location even when all applications and system services are individually set never to request this data.

Apple initially said the company did not see any privacy concerns and that the location tracking icon (a small, upward-facing arrow to the left of the battery icon) appears for system services that do not have a switch in the iPhone’s settings menu.

Apple later acknowledged the mysterious location requests were related to the inclusion of an Ultra Wideband chip in iPhone 11, Pro and Pro Max devices.

The company further explained that the location information indicator appears because the device periodically checks to see whether it is being used in a handful of countries for which Apple hasn’t yet received approval to deploy Ultra Wideband.

Apple also stressed it doesn’t use the UWB feature to collect user location data, and that this location checking resided “entirely on the device.” Still, it’s nice that iPhone 11 users will now have a disable the feature if they want.

Spotted by journalist Brandon Butch and published on Twitter last week, the new toggle switch to turn off UWB now exists in the “Networking & Wireless” settings in beta versions of iOS 13.3.1, under Locations Services > System Services. Beta versions are released early to developers to help iron out kinks in the software, and it’s not clear yet when 13.3.1 will be released to the general public.

Patch Tuesday, January 2020 Edition

Microsoft today released updates to plug 50 security holes in various flavors of Windows and related software. The patch batch includes a fix for a flaw in Windows 10 and server equivalents of this operating system that prompted an unprecedented public warning from the U.S. National Security Agency. This month also marks the end of mainstream support for Windows 7, a still broadly-used operating system that will no longer be supplied with security updates.

As first reported Monday by KrebsOnSecurity, Microsoft addressed a severe bug (CVE-2020-0601) in Windows 10 and Windows Server 2016/19 reported by the NSA that allows an attacker to spoof the digital signature tied to a specific piece of software. Such a weakness could be abused by attackers to make malware appear to be a benign program that was produced and signed by a legitimate software company.

An advisory (PDF) released today by the NSA says the flaw may have far more wide-ranging security implications, noting that the “exploitation of the vulnerability allows attackers to defeat trusted network connections and deliver executable code while appearing as legitimately trusted entities.”

“NSA assesses the vulnerability to be severe and that sophisticated cyber actors will understand the underlying flaw very quickly and, if exploited, would render the previously mentioned platforms as fundamentally vulnerable,” the advisory continues. “The consequences of not patching the vulnerability are severe and widespread.”

Matthew Green, an associate professor in the computer science department at Johns Hopkins University, said the flaw involves an apparent implementation weakness in a component of recent Windows versions responsible for validating the legitimacy of authentication requests for a panoply of security functions in the operating system.

Green said attackers can use this weakness to impersonate everything from trusted Web sites to the source of software updates for Windows and other programs.

“Imagine if I wanted to pick the lock in your front door,” Green analogized. “It might be hard for me to come up with a key that will open your door, but what if I could tamper with or present both the key and the lock at the same time?”

Kenneth White, security principal at the software company MongoDB, equated the vulnerability to a phone call that gets routed to a party you didn’t intend to reach.

“You pick up the phone, dial a number and assume you’re talking to your bank or Microsoft or whomever, but the part of the software that confirms who you’re talking to is flawed,” White said. “That’s pretty bad, especially when your system is saying download this piece of software or patch automatically and it’s being done in the background.”

Both Green and White said it likely will be a matter of hours or days before security researchers and/or bad guys work out ways to exploit this bug, given the stakes involved. Indeed, already this evening KrebsOnSecurity has seen indications that people are teasing out such methods, which will likely be posted publicly online soon.

According to security vendor Qualys, only eight of the 50 flaws fixed in today’s patch roundup from Microsoft earned the company’s most dire “critical” rating, a designation reserved for bugs that can be exploited remotely by malware or miscreants to seize complete control over the target computer without any help from users.

Once again, some of those critical flaws include security weaknesses in the way Windows implements Remote Desktop connections, a feature that allows systems to be accessed, viewed and controlled as if the user was seated directly in front of the remote computer. Other critical patches include updates for the Web browsers and Web scripting engines built into Windows, as well as fixes for ASP.NET and the .NET Framework.

The security fix for the CVE-2020-0601 bug and others detailed in this post will be offered to Windows users as part of a bundle of patches released today by Microsoft. To see whether any updates are available for your Windows computer, go to the Start menu and type “Windows Update,” then let the system scan for any available patches.

Keep in mind that while staying up-to-date on Windows patches is a must, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re not losing your mind when the odd buggy patch causes problems booting the system. So do yourself a favor and backup your files before installing any patches. Windows 10 even has some built-in tools to help you do that, either on a per-file/folder basis or by making a complete and bootable copy of your hard drive all at once.

Today also marks the last month in which Microsoft will ship security updates for Windows 7 home/personal users. I count myself among some 30 percent of Windows users who still like and (ab)use this operating system in one form or another, and am sad that this day has come to pass. But if you rely on this OS for day-to-day use, it’s probably time to think about upgrading to something newer.

That might be a computer with Windows 10. Or maybe you have always wanted that shiny MacOS computer. If cost is a primary motivator and the user you have in mind doesn’t do much with the system other than browsing the Web, perhaps a Chromebook or an older machine with a recent version of Linux is the answer. Whichever system you choose, it’s important to pick one that fits the owner’s needs and provides security updates on an ongoing basis.

As always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may chime in here with some helpful tips.

Cryptic Rumblings Ahead of First 2020 Patch Tuesday

Sources tell KrebsOnSecurity that Microsoft Corp. is slated to release a software update on Tuesday to fix an extraordinarily serious security vulnerability in a core cryptographic component present in all versions of Windows. Those sources say Microsoft has quietly shipped a patch for the bug to branches of the U.S. military and to other high-value customers/targets that manage key Internet infrastructure, and that those organizations have been asked to sign agreements preventing them from disclosing details of the flaw prior to Jan. 14, the first Patch Tuesday of 2020.

According to sources, the vulnerability in question resides in a Windows component known as crypt32.dll, a Windows module that Microsoft says handles “certificate and cryptographic messaging functions in the CryptoAPI.” The Microsoft CryptoAPI provides services that enable developers to secure Windows-based applications using cryptography, and includes functionality for encrypting and decrypting data using digital certificates.

A critical vulnerability in this Windows component could have wide-ranging security implications for a number of important Windows functions, including authentication on Windows desktops and servers, the protection of sensitive data handled by Microsoft’s Internet Explorer/Edge browsers, as well as a number of third-party applications and tools.

Equally concerning, a flaw in crypt32.dll might also be abused to spoof the digital signature tied to a specific piece of software. Such a weakness could be exploited by attackers to make malware appear to be a benign program that was produced and signed by a legitimate software company.

This component was introduced into Windows more than 20 years ago — back in Windows NT 4.0. Consequently, all versions of Windows are likely affected (including Windows XP, which is no longer being supported with patches from Microsoft).

Microsoft has not yet responded to requests for comment. However, KrebsOnSecurity has heard rumblings from several sources over the past 48 hours that this Patch Tuesday (tomorrow) will include a doozy of an update that will need to be addressed immediately by all organizations running Windows.

Update 7:49 p.m. ET: Microsoft responded, saying that it does not discuss the details of reported vulnerabilities before an update is available. The company also said it does “not release production-ready updates ahead of regular Update Tuesday schedule. “Through our Security Update Validation Program (SUVP), we release advance versions of our updates for the purpose of validation and interoperability testing in lab environments,” Microsoft said in a written statement. “Participants in this program are contractually disallowed from applying the fix to any system outside of this purpose and may not apply it to production infrastructure.”

Original story:

Will Dormann, a security researcher who authors many of the vulnerability reports for the CERT Coordination Center (CERT-CC), tweeted today that “people should perhaps pay very close attention to installing tomorrow’s Microsoft Patch Tuesday updates in a timely manner. Even more so than others. I don’t know…just call it a hunch?” Dormann declined to elaborate on that teaser.

It could be that the timing and topic here (cryptography) is nothing more than a coincidence, but KrebsOnSecurity today received a heads up from the U.S. National Security Agency (NSA) stating that NSA’s Director of Cybersecurity Anne Neuberger is slated to host a call on Jan. 14 with the news media that “will provide advanced notification of a current NSA cybersecurity issue.”

The NSA’s public affairs folks did not respond to requests for more information on the nature or purpose of the discussion. The invitation from the agency said only that the call “reflects NSA’s efforts to enhance dialogue with industry partners regarding its work in the cybersecurity domain.”

Stay tuned for tomorrow’s coverage of Patch Tuesday and possibly more information on this particular vulnerability.

Patch Tuesday, December 2019 Edition

Microsoft today released updates to plug three dozen security holes in its Windows operating system and other software. The patches include fixes for seven critical bugs — those that can be exploited by malware or miscreants to take control over a Windows system with no help from users — as well as another flaw in most versions of Windows that is already being exploited in active attacks.

By nearly all accounts, the chief bugaboo this month is CVE-2019-1458, a vulnerability in a core Windows component (Win32k) that is present in Windows 7 through 10 and Windows Server 2008-2019. This bug is already being exploited in the wild, and according to Recorded Future the exploit available for it is similar to CVE-2019-0859, a Windows flaw reported in April that was found being sold in underground markets.

CVE-2019-1458 is what’s known as a “privilege escalation” flaw, meaning an attacker would need to previously have compromised the system using another vulnerability. Handy in that respect is CVE-2019-1468, a similarly widespread critical issue in the Windows font library that could be exploited just by getting the user to visit a hacked or malicious Web site.

Chris Goettl, director of security at Ivanti, called attention to a curious patch advisory Microsoft released today for CVE-2019-1489, which is yet another weakness in the Windows Remote Desktop Protocol (RDP) client, a component of Windows which lets users view and manage their system from a remote computer. What’s curious about this advisory is that it applies only to Windows XP Service Pack 3, which is no longer receiving security updates.

“The Exploitability Assessment for Latest Software Release and Older Software Release is 0, which is usually the value reserved for a vulnerability that is known to be exploited, yet the Exploited value was currently set to ‘No’ as the bulletin was released today,” Goettl said. “If you look at the Zero Day from this month (CVE-2019-1458) the EA for Older Software Release is ‘0 – Exploitation Detected.’ An odd discrepancy on top of a CVE advisory for an outdated OS. It is very likely this is being exploited in the wild.”

Microsoft didn’t release a patch for this bug on XP, and its advisory on it is about as sparse as they come. But if you’re still depending on Windows XP for remote access, you likely have bigger security concerns. Microsoft has patched many critical RDP flaws in the past year. Even the FBI last year encouraged users to disable it unless needed, citing flawed encryption mechanisms in older versions and a lack of access controls which make RDP a frequent entry point for malware and ransomware.

Speaking of no-longer-supported Microsoft operating systems, Windows 7 and Windows Server 2008 will cease receiving security updates after the next decade’s first Patch Tuesday comes to pass on January 14, 2020. While businesses and other volume-license purchasers will have the option to pay for further fixes after that point, all other Windows 7 users who want to stick with Windows will need to consider migrating to Windows 10 soon.

Windows 10 likes to install patches and sometimes feature updates all in one go and reboot your computer on its own schedule, but you don’t have to accept this default setting. Windows Central has a useful guide on how to disable or postpone automatic updates until you’re ready to install them. For all other Windows OS users, if you’d rather be alerted to new updates when they’re available so you can choose when to install them, there’s a setting for that in Windows Update. To get there, click the Windows key on your keyboard and type “windows update” into the box that pops up.

Keep in mind that while staying up-to-date on Windows patches is a good idea, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re probably not losing your mind when the odd buggy patch causes problems booting the system. So do yourself a favor and backup your files before installing any patches.

And as always, if you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a better-than-even chance other readers have experienced the same and may even chime in here with some helpful tips.

Finally, once again there are no security updates for Adobe Flash Player this month (there is a non-security update available), but Adobe did release critical updates for Windows and macOS versions of its Acrobat and PDF Reader that fix more than 20 vulnerabilities in these products. Photoshop and ColdFusion 2018 also received security updates today. Links to advisories here.

Patch Tuesday, November 2019 Edition

Microsoft today released updates to plug security holes in its software, including patches to fix at least 74 weaknesses in various flavors of Windows and programs that run on top of it. The November updates include patches for a zero-day flaw in Internet Explorer that is currently being exploited in the wild, as well as a sneaky bug in certain versions of Office for Mac that bypasses security protections and was detailed publicly prior to today’s patches.

More than a dozen of the flaws tackled in this month’s release are rated “critical,” meaning they involve weaknesses that could be exploited to install malware without any action on the part of the user, except for perhaps browsing to a hacked or malicious Web site or opening a booby-trapped file attachment.

Perhaps the most concerning of those critical holes is a zero-day flaw in Internet Exploder Explorer (CVE-2019-1429) that has already seen active exploitation. Today’s updates also address two other critical vulnerabilities in the same Windows component that handles various scripting languages.

Microsoft also fixed a flaw in Microsoft Office for Mac (CVE-2019-1457) that could allow attackers to bypass security protections in some versions of the program.

Macros are bits of computer code that can be embedded into Office files, and malicious macros are frequently used by malware purveyors to compromise Windows systems. Usually, this takes the form of a prompt urging the user to “enable macros” once they’ve opened a booby-trapped Office document delivered via email. Thus, Office has a feature called “disable all macros without notification.”

But Microsoft says all versions of Office still support an older type of macros that do not respect this setting, and can be used as a vector for pushing malwareWill Dormann of the CERT/CC has reported that Office 2016 and 2019 for Mac will fail to prompt the user before executing these older macro types if the “Disable all macros without notification” setting is used.

Other Windows applications or components receiving patches for critical flaws today include Microsoft Exchange and Windows Media Player. In addition, Microsoft also patched nine vulnerabilities — five of them critical — in the Windows Hyper-V, an add-on to the Windows Server OS (and Windows 10 Pro) that allows users to create and run virtual machines (other “guest” operating systems) from within Windows.

Although Adobe typically issues patches for its Flash Player browser component on Patch Tuesday, this is the second month in a row that Adobe has not released any security updates for Flash. However, Adobe today did push security fixes for a variety of its creative software suites, including Animate, Illustrator, Media Encoder and Bridge. Also, I neglected to note last month that Adobe released a critical update for Acrobat/Reader that addressed at least 67 bugs, so if you’ve got either of these products installed, please be sure they’re patched and up to date.

Finally, Google recently fixed a zero-day flaw in its Chrome Web browser (CVE-2019-13720). If you use Chrome and see an upward-facing arrow to the right of the address bar, you have an update pending; fully closing and restarting the browser should install any available updates.

Now seems like a good time to remind all you Windows 7 end users that Microsoft will cease shipping security updates after January 2020 (this end-of-life also affects Windows Server 2008 and 2008 R2). While businesses and other volume-license purchasers will have the option to pay for further fixes after that point, all other Windows 7 users who want to stick with Windows will need to consider migrating to Windows 10 soon.

Standard heads-up: Windows 10 likes to install patches all in one go and reboot your computer on its own schedule. Microsoft doesn’t make it easy for Windows 10 users to change this setting, but it is possible. For all other Windows OS users, if you’d rather be alerted to new updates when they’re available so you can choose when to install them, there’s a setting for that in Windows Update. To get there, click the Windows key on your keyboard and type “windows update” into the box that pops up.

Keep in mind that while staying up-to-date on Windows patches is a good idea, it’s important to make sure you’re updating only after you’ve backed up your important data and files. A reliable backup means you’re probably not freaking out when the odd buggy patch causes problems booting the system. So do yourself a favor and backup your files before installing any patches.

As ever, if you experience glitches or problems installing any of these patches this month, please feel free to leave a comment about it below; there’s a decent chance other readers have experienced the same and may even chime in here with some helpful tips.

Update, Nov. 13, 11:34 a.m.: An earlier version of this story misstated some of the findings from CERT/CC, and misspelled the name of the researcher. The above post has been corrected.