The ultimate Patch Tuesday of 2023 is upon us, with Microsoft Corp. right this moment releasing fixes for a comparatively small variety of safety holes in its Home windows working techniques and different software program. Much more uncommon, there are not any recognized “zero-day” threats concentrating on any of the vulnerabilities in December’s patch batch. Nonetheless, 4 of the updates pushed out right this moment tackle “important” vulnerabilities that Microsoft says could 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 could be present in numerous Microsoft functions, together with Workplace, Outlook, Skype and Groups.
“Within the worst-case state of affairs, Microsoft means that merely receiving an electronic mail could 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 most likely 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 gadgets share an Web connection. Whereas CVE-2023-35641 earned a excessive vulnerability severity rating (a CVSS score 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 functions might flip it on).
Satnam Narang, senior workers analysis engineer at Tenable, notes that numerous the non-critical patches launched right this moment have been recognized by Microsoft as “extra more likely 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 through 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 could possibly be leveraged as a part of an NTLM relay or “cross the hash” assault, which lets an attacker masquerade as a official 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 through Microsoft’s Preview Pane, which lowers the severity of this flaw.”
As regular, the SANS Web Storm Heart has a superb roundup on the entire patches launched right this moment and listed by severity. Home windows customers, please think about backing up your information and/or imaging your system earlier than making use of any updates. And be at liberty to pontificate within the feedback for those who expertise any difficulties because of these patches.
