Malicious PDF — malware analysis report

Static analysis result for SHA-256 39de29d77178297f…

MALICIOUS

PDF

292.3 KB
MD5: fbe66d5cef16f3414575a791bf81ff4d SHA-1: c8d5ec25487bf5017f827367fb4105be52470dd6 SHA-256: 39de29d77178297f68e7f11d79486a3cdfcc7f59fd6cf56a1feaa821df37d9ff
76 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript, named 'javascript_obj0008_000.js', is the primary artifact and is likely responsible for executing the malicious payload, potentially downloading additional stages or performing other malicious actions.

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
e95a77e6bde30862e0874abd9bea078a371f9f55c55a4ecbf124150ade6f09e5
pdf-javascript-stream PDF /JS object 8 at offset 0x1CE 99528 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).