Detect CVE-2025-6218: RARLAB WinRAR Path Traversal Exploitation in Microsoft Sentinel
Detects exploitation of CVE-2025-6218, a path traversal vulnerability in RARLAB WinRAR. Attackers can craft malicious archive files that, when extracted, write files outside the intended extraction directory, enabling arbitrary file placement on the victim system. This vulnerability is actively exploited in the wild (CISA KEV) and can lead to code execution, persistence, or privilege escalation by dropping malicious files to sensitive locations such as startup folders, system directories, or application data paths.
MITRE ATT&CK
- Tactic
- Initial Access Execution Persistence
KQL Detection Query
let suspiciousPaths = dynamic(['\\AppData\\Roaming\\Microsoft\\Windows\\Start Menu\\Programs\\Startup', '\\ProgramData\\Microsoft\\Windows\\Start Menu\\Programs\\Startup', '\\Windows\\System32\\', '\\Windows\\SysWOW64\\', '\\Windows\\Tasks\\']);
DeviceFileEvents
| where TimeGenerated > ago(7d)
| where InitiatingProcessFileName =~ "WinRAR.exe" or InitiatingProcessParentFileName =~ "WinRAR.exe"
| where ActionType in ("FileCreated", "FileModified")
| extend FolderPathLower = tolower(FolderPath)
| where FolderPathLower has_any (suspiciousPaths) or FolderPath matches regex @'\.\.[\\/]'
| project TimeGenerated, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, FolderPath, FileName, SHA256, InitiatingProcessAccountName
| extend RiskIndicator = case(
FolderPathLower has "startup", "DropInStartupFolder",
FolderPathLower has "system32", "DropInSystem32",
FolderPathLower has "syswow64", "DropInSysWOW64",
FolderPathLower has "\\tasks\\", "DropInTasksFolder",
"PathTraversalSuspected"
)
| order by TimeGenerated descDetects WinRAR writing files to sensitive directories outside a normal extraction path, indicative of CVE-2025-6218 path traversal exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate WinRAR installations updating themselves to system paths
- IT administrators extracting archives to system directories for deployment
- Software installers packaged as RAR archives that write to expected system paths
Other platforms for CVE-2025-6218
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1WinRAR Path Traversal to Startup Folder
Expected signal: Sysmon Event ID 11 (FileCreate) with Image=WinRAR.exe and TargetFilename pointing to the Startup folder path
- Test 2WinRAR Extraction with Relative Path Traversal Sequence
Expected signal: Sysmon Event ID 11 with TargetFilename containing path traversal sequence and WinRAR.exe as the initiating process
- Test 3WinRAR Drop Executable to Windows Tasks Directory
Expected signal: Sysmon Event ID 11 (FileCreate) with Image containing WinRAR.exe and TargetFilename matching C:\Windows\Tasks\*
Unlock Pro Content
Get the full detection package for CVE-2025-6218 including response playbook, investigation guide, and atomic red team tests.