Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability
Microsoft · Windows
The flaw is a use-after-free vulnerability in the Ancillary Function Driver for WinSock, a component of Microsoft Windows. An attacker who already has low-privilege authorized access on the local machine, with no user interaction required, can exploit it to elevate privileges.
Null pointer dereference in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 5/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.How attackers get in
What they do
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited the day it was disclosed. Public exploit code (PoC-in-GitHub) appeared 4 months after disclosure.
- Public exploit codePoC-in-GitHub+4 mo
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
5 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 5Resource DevelopmentTA0042
This use-after-free vulnerability in Windows has been exploited by attackers to gain SYSTEM-level privileges, leading to remote code execution, full system compromise, the modification of system processes to establish persistence on the machine, and the deployment of malware such as credential harvesters and ransomware.
ExecutionTA0002
PersistenceTA0003
Privilege EscalationTA0004
Credential AccessTA0006
Detection
0 rules for this CVE · 172 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2025-32709 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Exploitation for Privilege EscalationT106831 general rules
- Exploiting CVE-2019-1388criticalstable
- Audit CVE Eventcriticaltest
- HackTool - SysmonEOP Executioncriticaltest
- InstallerFileTakeOver LPE CVE-2021-41379 File Create Eventcriticaltest
- Possible Coin Miner CPU Priority Paramcriticaltest
- Potential CVE-2021-41379 Exploitation Attemptcriticaltest
- Potential SystemNightmare Exploitation Attemptcriticaltest
- Sudo Privilege Escalation CVE-2019-14287 - Builtincriticaltest
Command and Scripting InterpreterT105995 general rules
- HackTool - Sliver C2 Implant Activity Patterncriticaltest
- Lazarus Group Activitycriticaltest
- REvil Kaseya Incident Malware Patternscriticaltest
- Turla Group Lateral Movementcriticaltest
- Windows Defender AMSI Trigger Detectedhighstable
- Windows Defender Threat Detectedhighstable
- Abusable DLL Potential Sideloading From Suspicious Locationhightest
- Add Insecure Download Source To Wingethightest
Create or Modify System ProcessT15439 general rules
- CodeIntegrity - Blocked Driver Load With Revoked Certificatehightest
- CodeIntegrity - Blocked Image/Driver Load For Policy Violationhightest
- KrbRelayUp Service Installationhightest
- PUA - Process Hacker Driver Loadhightest
- Service Installed By Unusual Client - Securityhightest
- Service Installed By Unusual Client - Systemhightest
- PUA - Process Hacker Executionmediumtest
- PUA - System Informer Driver Loadmediumtest
OS Credential DumpingT100337 general rules
- Antivirus - Password Dumper Signaturecriticalstable
- HackTool - Rubeus Executioncriticalstable
- Hacktool Execution - Imphashcriticaltest
- Potential Credential Dumping Via LSASS Process Clonecriticaltest
- WCE wceaux.dll Accesscriticaltest
- HackTool - Potential Remote Credential Dumping Activity Via CrackMapExec Or Impacket-Secretsdumphightest
- HackTool - Rubeus Execution - ScriptBlockhightest
- Hacktool Execution - PE Metadatahightest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 30, 202629 Oct 2026
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- 44 more on OTX