Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf5a7db31159df22…

MALICIOUS

PDF

14.4 KB Created: 2009-11-15 19:41:70 Authoring application: PDF Library 4.3.9 (via PDF Library 3.9.7)
MD5: df67cb7c320fc75d64b35f9dca4052be SHA-1: 30a34d6b4c4167d632c871e09f5f7814b8e6622b SHA-256: cf5a7db31159df22a302d58b6272b8ec591db8f7a6f82184d7e22e795589817e
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The critical ClamAV detection and ML classifier output strongly indicate malicious intent. The presence of PDF JavaScript actions and an embedded JS stream suggests the file is designed to exploit vulnerabilities within the PDF reader to execute arbitrary code. The embedded JavaScript is likely responsible for downloading and executing a second-stage payload, as indicated by the ClamAV detection signature 'Win.Trojan.Agent-36166'.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 4

  • ClamAV: Win.Trojan.Agent-36166 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Agent-36166
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
2ebcd3a1227da84418151f588af94dcd573581a9de498df20767e5d25a318b40
pdf-javascript-stream PDF /JS object 7 at offset 0x1A5 74804 bytes
Detection
ClamAV: Win.Trojan.Agent-36166
Obfuscation or payload: unlikely