Malicious PDF — malware analysis report

Static analysis result for SHA-256 7b137e33b70aadd8…

MALICIOUS

PDF

50.4 KB Created: 2010-06-29 10:14:47 +08:00 Authoring application: Acrobat 编辑器 8.0 (via Adobe Acrobat 8.0)
MD5: 8123692b312bd45e82cc8fdadeb26147 SHA-1: f744939d78d36d81a708bcaaafbb645b68fa0fa9 SHA-256: 7b137e33b70aadd852969528bc2175b03805cc97ad7b3d866f90ef7cdaea1ab8
288 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF sample contains embedded JavaScript that leverages the CVE-2009-4324 vulnerability (media.newPlayer) to achieve code execution. The JavaScript is heavily obfuscated but ultimately calls media.newPlayer, a known exploit trigger. The script also contains a large, encoded string that likely represents the second-stage payload or its download URL, though it was truncated in the provided evidence. The presence of multiple PDF-specific exploit heuristics and the ML classifier strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 8

  • media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324
    PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Suspicious extracted artifact medium 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.
  • 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 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0021_000.js
dd957791cf3ea91d9aa5ef655b3a1d6c4a92036e875c2437657f276955dab674		 pdf-javascript-stream PDF /JS object 21 at offset 0x514 2371 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s). Carved artifact contains 1 long hex-escaped blob(s).
legacy_pdfkit_stage_000.js
42c3f4df375ff6f58ff655cc4f88b5cc28f0dd33b978390db3538684a6219b74		 deobfuscated-js string-concatenation normalized Acrobat API aliases at offset 0x514 126 bytes
polyglot_child_pdf_off0000b506.pdf
84d1779a2aebc787d2e0a6379189b013668a186744f072b003cf9595b2bf2bf6		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0xB506 5312 bytes

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