CVE-2011-2005 — Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerab

afd.sys in the Ancillary Function Driver in Microsoft Windows XP SP2 and SP3 and Server 2003 SP2 does not properly validate user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application, aka "Ancillary Function Driver Elevation

01What is this vulnerability?

afd.sys in the Ancillary Function Driver in Microsoft Windows XP SP2 and SP3 and Server 2003 SP2 does not properly validate user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application, aka "Ancillary Function Driver Elevation of Privilege Vulnerability."

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2022-03-28. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

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07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2011-10-12T01:00:00.000Z
• Last modified: 2025-10-22T00:05:49.314Z
• Added to CISA KEV: 2022-03-28
• BOD 22-01 due: 2022-04-18

09References

• oval.cisecurity.org — https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3…
• docs.microsoft.com — https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-08…