‘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.