#VU51304 Time-of-check Time-of-use (TOCTOU) Race Condition in Windows and Windows Server


Published: 2021-03-09 | Updated: 2021-04-30

Vulnerability identifier: #VU51304

Vulnerability risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-1640

CWE-ID: CWE-367

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a race condition within the Print Spooler service. A local user can create a directory junction and force the Print Spooler service to delete arbitrary files on the system. Successful exploitation of the vulnerability may result in denial of service.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 10 - 10 2004, 7, 8.1 - 8.1 RT

Windows Server: 2008 - 2019 2004


External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1640
http://www.zerodayinitiative.com/advisories/ZDI-21-493/


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.


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