Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8e41a4dbeaa2e3a…

MALICIOUS

PDF

3.8 KB
MD5: c362af41074b2b17f34af5d24b2ab948 SHA-1: 8ba1a995404894422189915cafcdd0ebeaa8bc21 SHA-256: c8e41a4dbeaa2e3a14760fe41490195b4198b70e05b67239f6fdbab466c6092b
142 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1566.002 Phishing: Spearphishing Attachment T1059.001 JavaScript

The file is a PDF that has been flagged by multiple heuristics and a machine learning classifier as malicious. It contains embedded JavaScript, utilizes obfuscation filters like ASCIIHexDecode and ASCII85Decode, and String.fromCharCode, indicating an attempt to hide malicious code. ClamAV also detected it as Pdf.Exploit.Agent-36178, confirming its exploit nature. The primary attack pattern involves luring a user to open a malicious PDF which then exploits a vulnerability.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Exploit.Agent-36178 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36178
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • ASCII85Decode filter (with exploit indicators) low PDF_FILTER_85
    ASCII85 encoding filter present alongside exploit delivery indicators — uncommon outside of obfuscation