A Home windows zero-day safety vulnerability below lively exploit leads Microsoft’s December 2024 Patch Tuesday safety replace, which hardly constitutes a sleigh of festive tidings for safety admins: A stocking filled with 71 patches.
The tech big unwrapped CVEs in Home windows and Home windows Parts, Workplace and Workplace Parts, SharePoint Server, Hyper-V, Defender for Endpoint, and System Heart Operations Supervisor.
This 12 months’s holiday-season entry brings the entire variety of patches for the 12 months to 1,020, Redmond’s second-most voluminous 12 months for fixes after 2020’s 1,250. Out of this month’s CVEs, 16 are rated as vital.
Home windows CLFS Zero-Day Permits Privilege Escalation
The actively exploited bug is tracked as CVE-2024-49138 (CVSS 7.8), a moderate-severity flaw within the Home windows Widespread Log File System (CLFS) Driver.
“CLFS is a logging service that helps person and kernel-mode operations,” defined Henry Smith, senior safety engineer at Automox, in an emailed evaluation. “Whereas the small print are nonetheless restricted, the basis trigger seemingly ties again to improper information validation. … Early indicators counsel that attackers would possibly exploit this bug through the use of Home windows APIs to govern log information or corrupt log information, triggering the vulnerability.”
The potential impression is substantial, he added, provided that an exploit results in SYSTEM-level privileges on Home windows Server. When paired with a distant code execution (RCE) bug, it is an ideal recipe for fully taking up a PC.
Satnam Narang, senior employees analysis engineer at Tenable, famous by way of e mail that ransomware operators particularly have “developed a penchant for exploiting CLFS elevation-of-privilege flaws over the previous few years.”
He famous, “not like superior persistent risk (APT) teams that sometimes concentrate on precision and endurance, ransomware operators and affiliates are centered on the smash-and-grab ways by any means essential. By utilizing elevation-of-privilege flaws like this one in CLFS, ransomware associates can transfer via a given community to be able to steal and encrypt information and start extorting their victims.”
Crucial Distant-Code Execution Vulnerabilities in LDAP, Hyper-V, RDP
The critical-severity CVE-2024-49112 (CVSS 9.8) is probably probably the most regarding CVE on this month’s stocking of distress. It is an unauthenticated RCE concern within the Home windows Light-weight Listing Entry Protocol (LDAP).
In line with Dustin Childs on the Zero Day Initiative (ZDI), cyberattackers can exploit the bug to compromise Area Controllers by sending a specifically crafted set of LDAP calls.
“Code execution happens on the degree of the LDAP service, which is elevated, however not SYSTEM,” Childs wrote in a blog post on Dec. 10. “Microsoft gives some … fascinating mitigation recommendation. They advocate disconnecting Area Controllers from the Web. Whereas that will cease this assault, I am undecided how sensible that will be for many enterprises. I like to recommend testing and deploying the patch shortly.”
One other vital RCE vulnerability to deal with shortly is CVE-2024-49117 (CVSS 8.8) in Home windows Hyper-V. An exploit would permit somebody on a visitor digital machine (VM) to execute code on the underlying host OS, or carry out a cross-VM assault.
“The excellent news right here is that the attacker does have to be authenticated,” Childs famous. “The dangerous information is that the attacker solely requires fundamental authentication — nothing elevated. If you’re working Hyper-V or have hosts on a Hyper-V server, you will positively need to get this patched shortly.”
A complete of 9 vital bugs have an effect on Home windows Distant Desktop Companies, with one (CVE-2024-49132, CVSS 8.1) permitting RCE by exploiting a use-after-free reminiscence situation.
“The exploit requires exact timing, making it a complicated assault,” Ryan Braunstein, safety supervisor at Automox, mentioned by way of e mail. “Particularly, if a person connects via the Distant Desktop Gateway function, an attacker might deliberately set off the use-after-free situation. Efficiently exploited, this vulnerability can permit attackers to execute their code remotely, gaining management of the system.”
Meaning exploitation is on the tough facet, however Braunstein cautioned that “over time, it is seemingly that cyberattackers develop instruments that simplify the assault course of. Till then, there aren’t any efficient workarounds, making instant patching your greatest probability to mitigate this danger.”
There are additionally eight different vital vulnerabilities that price 8.1 on the CVSS scale in Distant Desktop Companies, together with 5 different UAF bugs (CVE-2024-49115, CVE-2024-49116, CVE-2024-49108, CVE-2024-49106, and CVE-2024-49128); CVE-2024-49123, which entails delicate information storage in improperly locked reminiscence; CVE-2024-49120, an insecure default variable initialization flaw; and CVE-2024-49119, arising from improper useful resource dealing with throughout RDP classes.
“These vulnerabilities underscore persistent issues in RDP components, together with reminiscence administration, timing, and operational dealing with,” mentioned Mike Walters, president and co-founder of Action1, by way of e mail. “[With] different root causes, [it shows that] attackers can exploit totally different aspects of RDP companies. Organizations ought to keep away from exposing RDP companies to the worldwide Web and implement strong safety controls to mitigate dangers. These flaws additional show the hazards of leaving RDP open and unprotected.”
Different December 2024 Safety Vulnerabilities to Patch Now
Safety specialists additionally flagged two different bugs for safety admins so as to add to their holiday checklists, together with an EoP vulnerability within the Home windows Resilient File System (ReFS).
Resilient File System (ReFS) is a file system designed for enhanced scalability and fault tolerance for virtualization environments, databases, and backups. It presents information resilience, storage effectivity, and improved efficiency.
“CVE-2024-49093 (CVSS 8.8) revolves round a scope change that permits an attacker to raise privileges from a low-privilege app container setting,” defined Seth Hoyt, senior safety engineer at Automox, by way of e mail. “Usually, app containers are designed to restrict a course of’s skill to entry information, reminiscence, and different sources. Exploiting this vulnerability allows attackers to flee these confines, gaining broader system-level entry. This implies they will work together with information, processes, and reminiscence beforehand out of attain.”
From there, cyberattackers might transfer laterally throughout the setting, he added.
The ultimate lump of coal known as out by researchers this month is an RCE vulnerability in Musik (CVE-2024-49063), a analysis venture on AI-created music.
“We have been questioning what bugs in AI would appear like, and up to now, they appear like deserialization vulnerabilities,” ZDI’s Childs mentioned. “That is what we’ve got right here. An attacker might acquire code execution by crafting a payload that executes upon deserialization. Neat.”
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