Malicious PDF — malware analysis report

Static analysis result for SHA-256 315324ca41ec5d6f…

MALICIOUS

PDF

9.4 KB Created: 2008-04-28 12:17:40 +03:00
MD5: 144d871b652bd26e1b539af7ece8d906 SHA-1: d4335e433c78c92ca4699f637bbe8048a447c82f SHA-256: 315324ca41ec5d6f5696912238ecb959643cb24c55c2707db60233634133fa6c
106 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

This PDF file exhibits multiple high-severity heuristic firings, including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL, indicating the presence and execution of obfuscated JavaScript. The ML classifier also flagged this PDF with a very high probability of being malicious. The embedded JavaScript stream, named 'javascript_obj0016_000.js', is the primary indicator of malicious activity. The use of eval() and String.fromCharCode() within the script strongly suggests it is designed to download and execute a second-stage payload, a common technique for malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 8

  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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)
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/iX/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0016_000.js
207fba1681ab327066c7b4fa53d1fea167de659c7f5e4847ac3c66f39abaf15e		 pdf-javascript-stream PDF /JS object 16 at offset 0x931 7066 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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