Microsoft Patch Tuesday, December 2023 Version – Krebs on Safety

The ultimate Patch Tuesday of 2023 is upon us, with Microsoft Corp. at this time releasing fixes for a comparatively small variety of safety holes in its Home windows working methods and different software program. Much more uncommon, there are not any recognized “zero-day” threats focusing on any of the vulnerabilities in December’s patch batch. Nonetheless, 4 of the updates pushed out at this time deal with “important” vulnerabilities that Microsoft says will be exploited by malware or malcontents to grab full management over a weak Home windows gadget with little or no assist from customers.

Among the many important bugs quashed this month is CVE-2023-35628, a weak point current in Home windows 10 and later variations, in addition to Microsoft Server 2008 and later. Kevin Breen, senior director of risk analysis at Immersive Labs, stated the flaw impacts MSHTML, a core part of Home windows that’s used to render browser-based content material. Breen notes that MSHTML additionally will be present in various Microsoft purposes, together with Workplace, Outlook, Skype and Groups.

“Within the worst-case state of affairs, Microsoft means that merely receiving an electronic mail can be sufficient to set off the vulnerability and provides an attacker code execution on the goal machine with none consumer interplay like opening or interacting with the contents,” Breen stated.

One other important flaw that in all probability deserves precedence patching is CVE-2023-35641, a distant code execution weak point in a built-in Home windows characteristic known as the Web Connection Sharing (ICS) service that lets a number of units share an Web connection. Whereas CVE-2023-35641 earned a excessive vulnerability severity rating (a CVSS ranking of 8.8), the risk from this flaw could also be restricted considerably as a result of an attacker would must be on the identical community because the goal. Additionally, whereas ICS is current in all variations of Home windows since Home windows 7, it isn’t on by default (though some purposes might flip it on).

Satnam Narang, senior employees analysis engineer at Tenable, notes that various the non-critical patches launched at this time have been recognized by Microsoft as “extra prone to be exploited.” For instance, CVE-2023-35636, which Microsoft says is an data disclosure vulnerability in Outlook. An attacker might exploit this flaw by convincing a possible sufferer to open a specifically crafted file delivered by way of electronic mail or hosted on a malicious web site.

Narang stated what makes this one stand out is that exploitation of this flaw would result in the disclosure of NTLM hashes, which might be leveraged as a part of an NTLM relay or “move the hash” assault, which lets an attacker masquerade as a professional consumer with out ever having to log in.

”It’s paying homage to CVE-2023-23397, an elevation of privilege vulnerability in Microsoft Outlook that was exploited within the wild as a zero day and patched within the March 2023 Patch Tuesday launch,” Narang stated. “Nevertheless, in contrast to CVE-2023-23397, CVE-2023-35636 shouldn’t be exploitable by way of Microsoft’s Preview Pane, which lowers the severity of this flaw.”

As standard, the SANS Web Storm Middle has a great roundup on the entire patches launched at this time and listed by severity. Home windows customers, please take into account backing up your knowledge and/or imaging your system earlier than making use of any updates. And be happy to pontificate within the feedback when you expertise any difficulties on account of these patches.