Suspicious Plink SSH Tunnel Used for Data Exfiltration
- Product
- windows
- Category
- process_creation
- Author
- HuntRule
- Published
- 2026-08-05
- Updated
- 2026-08-28
ATT&CK techniques
ExfiltrationRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Impact
What it detects
This rule detects the PuTTY plink client invoked with port forwarding and non-interactive SSH options consistent with tunneling and exfiltration. Microsoft observed Marbled Dust using plink to exfiltrate collected data over SSH from Output Messenger victims. Command-line SSH tunneling by an espionage actor over an encrypted channel is used to bypass egress monitoring, so this pattern warrants investigation.
Reporting behind it
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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