huntrule

Windows Application Logs: Detect WSUS deserialization exploitation via InvalidCastException indicators

Flags WSUS (EventID 7053) application log errors matching invalid cast/object data provider strings indicative of CVE-2025-59287 exploitation.

FreeReviewedSigma · High · v5
Product
windows
Service
application
Author
Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2025-10-31
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access → Execution

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule identifies exploitation attempts against Windows Server Update Services by matching specific deserialization-related cast exception strings in WSUS application logs. Attackers may exploit this class of issues to trigger harmful object deserialization behavior, so these error patterns can serve as high-signal indicators. It relies on Windows application log events with EventID 7053 where Provider_Name is Windows Server Update Services and the event message contains the listed InvalidCastException and related object-casting text.

Reporting behind it

Related detections9 linkedT1190 — drag to rearrange
Windows Process Creation: Suspicious cmd.exe or PowerShell Child of WSUS (wsusservice.exe)
Zeek HTTP POST to /wsman without Authorization — Possible OMIGOD unauthenticated RCE (CVE-2021-38647)
Cleo Autorun Exploitation via Healthcheck File Drop
Suspicious SharePoint Worker Process Spawning Command Interpreter via ToolShell
Malicious IIS Worker Process Spawning Command Shell Reconnaissance
Potential StyleSmuggler (CVE-2026-75650) Exploitation Attempt - Magento GraphQL Styles Parameter (via webserver)
Cisco IOS XE Configuration Change by Web UI WSMA User
Possible React2Shell CVE-2025-55182 Prototype Pollution Exploitation
Possible Next.js Middleware Auth Bypass via X-Middleware-Subrequest Header (CVE-2025-29927)
Windows Application Logs: Detect WSUS deserialization exploitation via InvalidCastException indicators
Pivot detection · T1190 · 9 related

Changelog

v5
  1. v5
    Candidate ingested via manual entry.2026-07-31
  2. v4
    Candidate ingested via manual entry.2026-07-31
  3. v3
    Candidate ingested via manual entry.2026-07-31
  4. v2
    Candidate ingested via manual entry.2026-07-31
  5. v1
    No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.