Privilege escalation in Microsoft Windows Common Log File System Driver

1) Incorrect conversion between numeric types

EUVDB-ID: #VU79225

Risk: Low

CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2023-36900

CWE-ID: CWE-681 - Incorrect Conversion between Numeric Types

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to incorrect integer conversion in Windows Common Log File System driver (clfs.sys). A local user can create a specially crafted BLF file to trigger an incorrect integer calculation before allocating a buffer and execute arbitrary code on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Windows: 10 - 11 22H2 10.0.22621.521

Windows Server: 2008 - 2022 20H2

CPE2.3

• cpe:2.3:o:microsoft:windows:*:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10:Gold:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10:S:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10:Mobile:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_20H2:10.0.19042.572:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_21H1:10.0.19043.985:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_21H2:10.0.19044.1288:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_1511:10.0.10586.3:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:*:*:*:*:*:*:*:*

External links

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-36900
https://www.zerodayinitiative.com/advisories/ZDI-23-1067/

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.