Malicious PDF — malware analysis report

Static analysis result for SHA-256 577d87b427fc6a1c…

MALICIOUS

PDF

156.8 KB Created: 2008-05-21 16:10:52 +08:00 Authoring application: Acrobat PDFMaker 6.0 for Word (via Acrobat Distiller 6.0 (Windows))
MD5: d83613b9a29e49c5b407943d7ab2f8a8 SHA-1: 00b9bebcbd67ac13a56c3478820a824caf0bfff1 SHA-256: 577d87b427fc6a1c3b5e614a40fdb48b608b86126b19d4816f69bdb5949de760
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file was flagged by a machine learning classifier as malicious and contains embedded JavaScript. The JavaScript stream and an embedded PDF artifact were extracted. The presence of JavaScript actions and unescape calls within the PDF, along with the ML classification, strongly suggests malicious intent, likely for downloading and executing further stages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

Heuristics 6

  • 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)
  • 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/pdfx/1.3/
    • http://ns.adobe.com/photoshop/1.0/
    • 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_obj0031_000.js
d11df98c7ee948d719272ddf277381778834180ea847575920fd07d7f7341ca2		 pdf-javascript-stream PDF /JS object 31 at offset 0x20B6 3242 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 19 eval/decoder/string-building token(s).
polyglot_child_pdf_off00023c6e.pdf
60412d2e52e35bdd0a96ce08d0261041215024a3dbe517b4f52ba3dccea5ef48		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x23C6E 14030 bytes

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