huntrule

Windows: Detect Microsoft Exchange CVE-2020-0688 exploitation via Eventlog errors

Identifies Exchange Control Panel error events containing a ViewState parameter consistent with CVE-2020-0688 exploitation attempts.

FreeReviewedSigma · High · v5
Product
windows
Service
application
Author
Florian Roth (Nextron Systems), wagga (SigmaHQ), DRL 1.1
Published
2020-02-29
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access

  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 flags Windows application log entries where the Microsoft Exchange Control Panel provider emits an Error event (EventID 4) and the record contains a ViewState parameter marker. An attacker exploiting CVE-2020-0688 may generate crafted Exchange requests that cause these error conditions to be logged. It relies on Windows Application event telemetry including EventID, Provider_Name, Level, and the presence of the '&__VIEWSTATE=' string in the event data.

Reporting behind it

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Windows: Detect Microsoft Exchange CVE-2020-0688 exploitation via Eventlog errors
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.