huntrule

Windows: Monitor access to Signal Desktop config.json and db.sqlite in AppData\Roaming

Alerts on unauthorized access attempts to Signal Desktop’s config.json (key) and db.sqlite (messages) in the default Roaming path.

FreeReviewedSigma · Medium · v2
Product
windows
Service
security
Author
Andreas Braathen (mnemonic.io) (SigmaHQ), DRL 1.1
Published
2025-10-19
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Cred 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 Security event 4663 for file access to Signal Desktop’s sensitive data files, specifically db.sqlite and config.json, under the default AppData\Roaming\Signal path. It matters because config.json contains the decryption key in plaintext, and db.sqlite stores locally saved messages, so access to both files can allow an attacker to decrypt message contents without the user’s credentials. The detection relies on audited file-system access events that include the accessed object name/type and are filtered to exclude accesses made by the Signal-related executables.

Reporting behind it

Related detections9 linkedT1003 — drag to rearrange
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Malicious WDigest UseLogonCredential Enablement For Credential Theft
Linux: Detect changes to fs.suid_dumpable enabling core dumps for SUID processes
Windows: Monitor access to Signal Desktop config.json and db.sqlite in AppData\Roaming
Pivot detection · T1003 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. 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.