CVE-2011-2005 Microsoft Ancillary Function Driver (afd.sys): privilege escalation
In plain words: Something running with limited rights can promote itself to full control. Turns a small foothold (like a malicious app) into administrator or system-level access.
Confirmed exploited by CISA on · US federal patch deadline Apr 18, 2022
What to do
- Install Microsoft's security update for Ancillary Function Driver (afd.sys). If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability
- Product
- Microsoft Ancillary Function Driver (afd.sys)
- CISA description
- afd.sys in the Ancillary Function Driver in Microsoft Windows does not properly validate user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application.
- Type of flaw
- Privilege escalation (CWE-264)
- Confirmed exploited
- Mar 28, 2022
- US federal patch deadline
- Apr 18, 2022
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Answering about CVE-2011-2005 ·
Questions about CVE-2011-2005
Is CVE-2011-2005 being exploited?
Yes. CISA added CVE-2011-2005 to its Known Exploited Vulnerabilities catalog on Mar 28, 2022, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2011-2005?
Install Microsoft's security update for Ancillary Function Driver (afd.sys). If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2011-2005?
Only if you use Microsoft Ancillary Function Driver (afd.sys). Aimed mostly at company systems — you are affected through the companies you use, not your own phone.