Malicious PDF — malware analysis report

Static analysis result for SHA-256 42640d68d9dcda0a…

MALICIOUS

PDF

291.8 KB
MD5: c8fb3bad69e9ce0574dcec8ebe1a8827 SHA-1: b2a92baaea67ebf772cbdf046678167e7e6da11e SHA-256: 42640d68d9dcda0a2043b804143f4958f047b4f01ff775a1efad2e40d398dcf4
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File: User Execution: Malicious File

The PDF contains embedded JavaScript, indicated by multiple heuristics including PDF_JAVASCRIPT and PDF_JS. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript file, javascript_obj0008_000.js, is likely responsible for executing the malicious payload, potentially involving obfuscated code as suggested by the static triage.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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)
  • 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_obj0008_000.js
5500190082dea3dae9576453dbbc2f9d382296f5868921d2251909f61d4ee5c0
pdf-javascript-stream PDF /JS object 8 at offset 0x1CE 99336 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).