Malicious PDF — malware analysis report

Static analysis result for SHA-256 4e1598f1a2ad7e04…

MALICIOUS

PDF

14.5 KB
MD5: db86547b2c548233b0b1407151673703 SHA-1: 6873fcde97d6568a9e8d56d9ee6bfd4304f9dde6 SHA-256: 4e1598f1a2ad7e047582ee74f0cc381acb332408f0f7df12f4cfed099932e973
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains embedded JavaScript, which is heavily obfuscated using String.fromCharCode and eval() calls. This script is likely responsible for downloading and executing a secondary payload, as indicated by the 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' heuristics. The extracted artifact 'javascript_obj0076_000.js' is also flagged as suspicious. The obfuscated nature of the script prevents a more detailed analysis of its specific actions.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Exploit.Dropped-94 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Dropped-94
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0076_000.js
c28effae366bd4b2a63fe29aea090a07947ae4e73aa9efc1cf87e16e006e7288
pdf-javascript-stream PDF /JS object 76 at offset 0x38AB 144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).