Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c7972b09aea409c…

MALICIOUS

PDF

174.0 KB Created: 2009-08-31 10:11:27 +08:00
MD5: 0f825bef3affd6fa69d456b3944376e9 SHA-1: cd7b96b7ab5fd949280213e181f77d0c5d68e2e7 SHA-256: 4c7972b09aea409c62d387f6194ec60600e63bc0b76172e2fde2c333cc52394e
104 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.003 Windows Command and Shell T1059.007 JavaScript/JScript

The PDF file was flagged as malicious by an ML classifier and contains embedded JavaScript. The JavaScript stream, identified as stream_004_off00000675.js, exhibits obfuscation techniques including the use of eval() and String.fromCharCode(), typical of downloaders. While the exact URL it attempts to contact is not directly visible due to obfuscation, the presence of these indicators strongly suggests it's designed to fetch and execute a second-stage payload. No specific malware family could be confidently identified.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8846

Heuristics 7

  • 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. (matched inside decoded stream)
  • 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. (matched inside decoded stream)
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload (matched inside decoded stream)
  • 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.
  • 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/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off00000675.js
331cf1ca2521e817c7d0a847c0653ee63e0fbe5fd30dcf1e4531b2ca1556a0e2		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x675 3658 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
objstm_0026_00.bin
c6b88e7ad5407bb6452cfebf80ef7ca1f6e716deaceda4e2898e10adf9bd3d5a		 pdf-objstm-decoded PDF /ObjStm 26 0 obj (inflated) 306 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.