Possible Progress WS_FTP Ad Hoc Deserialization via AHT_DEFAULT_UPLOAD_PARAMETER Marker

ATT&CK techniques

Initial Access

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

What it detects

This rule detects multipart form-data uploads to WS_FTP Ad Hoc that carry the AHT_DEFAULT_UPLOAD_PARAMETER marker, matching the .NET BinaryFormatter deserialization exploit for CVE-2023-40044 documented by Assetnote. The marker delimits a base64 serialized object that the IIS module deserializes into code execution. Presence of this internal marker in a request body indicates targeted exploitation of the WS_FTP HTTP module.

Reporting behind it

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Possible Progress WS_FTP Ad Hoc Deserialization via AHT_DEFAULT_UPLOAD_PARAMETER Marker

Pivot detection · T1190 · 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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