Possible Aspera Faspex Pre-Auth RCE via YAML Deserialization in package_relay (via webserver)

ATT&CK techniques

Initial Access → Execution

Recon
Resource Dev
Initial Access
- T1190Exploit Public-Facing Application
Execution
- T1059Command and Scripting Interpreter
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects POST requests to the Aspera Faspex package_relay relay_package endpoint, the injection point for a pre-auth RCE where the external_emails field carries a serialized YAML payload deserialized by YAML.load. Attackers abuse this Ruby on Rails unsafe deserialization to execute arbitrary commands. Detecting it surfaces exploitation attempts against internet-facing Faspex servers.

Reporting behind it

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Possible Aspera Faspex Pre-Auth RCE via YAML Deserialization in package_relay (via webserver)

Pivot detection · T1059 · 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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