Rhysida Ransomware Encrypted File Extension Created

ATT&CK techniques

Impact

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
- T1486Data Encrypted for Impact

What it detects

This rule detects files being renamed with the .rhysida extension appended by Rhysida ransomware during encryption. Rhysida uses ChaCha20 to encrypt victim files and marks each with this extension. A burst of such file events indicates active mass encryption on the host.

Reporting behind it

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Malicious CACTUS Ransomware Note and Encrypted File Artifacts (via file_event)

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Rhysida Ransomware Encrypted File Extension Created

Pivot detection · T1486 · 9 related

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

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