Windows Common Log File System Driver Flaw Allows Attackers to Escalate Privileges

Microsoft addressed a critical security flaw (CVE-2025-32713) in the Windows Common Log File System (CLFS) driver during its June 2025 Patch Tuesday.

The heap-based buffer overflow vulnerability enables local attackers to escalate privileges to SYSTEM-level access, posing significant risks to enterprise environments.

Anatomy of CVE-2025-32713

The vulnerability stems from improper memory handling in the CLFS driver (CWE-122), which manages transaction logs for applications and system services.

Attackers can exploit this by:

• Triggering a heap overflow via crafted log operations.
• Corrupting adjacent memory structures to redirect execution flow.
• Gaining NT AUTHORITY\SYSTEM privileges without user interaction.

powershell# Detection script for suspicious CLFS activity
Get-Process | Where-Object { $_.ProcessName -eq "dllhost" -and $_.Modules.ModuleName -match "clfs" }

This PowerShell snippet identifies processes like dllhost.exe interacting abnormally with clfs.sys—a key indicator of exploitation.

Exploitation Mechanics and Observed Tactics

The flaw’s local attack vector (AV:L ...