Malicious PDF — malware analysis report

Static analysis result for SHA-256 22a9ff3db7b86e12…

MALICIOUS

PDF

84.1 KB Created: 2010-03-30 17:05:37 +08:00 Authoring application: PScript5.dll Version 5.2 (via Acrobat Distiller 6.0.1 (Windows))
MD5: a3b955f4365ab7343c0fda522156de06 SHA-1: bb5ee201044df79132b95635ea7f2b4284eb5a14 SHA-256: 22a9ff3db7b86e124fb0451fcb85e5152cd38c5eb7169d774807091e5b975ddf
158 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream is heavily obfuscated, utilizing eval() and unescape() calls, as evidenced by PDF_EVAL and PDF_UNESCAPE firings. A secondary embedded PDF was also found with similar suspicious findings. The primary function of the embedded JavaScript appears to be downloading and executing a second-stage payload, as suggested by the 'EXTRACTED_FILE_STATIC_TRIAGE' heuristic flagging script obfuscation indicators and the presence of a JavaScript file. The confidence is slightly reduced due to the obfuscation making precise analysis of the script's exact actions difficult.

Heuristics 7

  • 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.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (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.
  • 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/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0014_000.js
f88a00e927e26df17805ed162ce7be240b356db723ca38aa13d59e510c6f437e		 pdf-javascript-stream PDF /JS object 14 at offset 0x2CC 4691 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).
polyglot_child_pdf_off00013826.pdf
5d1a7bab96c6cdecbfa015528b426866f21073a9a631dc8106479c86fd3208cf		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x13826 6177 bytes

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