Malicious PDF — malware analysis report

Static analysis result for SHA-256 24c3ec2d1884c0d4…

MALICIOUS

PDF

165.3 KB Created: 2009-06-25 09:37:31 +08:00 Authoring application: Acrobat PDFMaker 7.0 for Word (via Acrobat Distiller 7.0 (Windows))
MD5: e9a96d2ed31a4c08559d46e7ce7d74e2 SHA-1: 97d1ea694aef059482baabaadbd82f25abdbf96d SHA-256: 24c3ec2d1884c0d43823367b3103dfc50358709a496914b4550c503afd66e63c
272 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

This PDF contains embedded JavaScript that utilizes unescape() to decode a payload. The decoded script appears to be designed to download and execute a second-stage payload, as indicated by the 'PDF_JS_EXPLOIT_CLUSTER' and 'POLYGLOT_CHILD_PDF_STATIC_TRIAGE' heuristics. The ClamAV detection 'Pdf.Dropper.Agent-7240120-0' further supports its malicious nature as a dropper. The script's obfuscated nature and the presence of a secondary embedded PDF suggest a multi-stage attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 9

  • 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.
  • ClamAV: Pdf.Dropper.Agent-7240120-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7240120-0
  • 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.
  • 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/pdf/1.3/
    • http://ns.adobe.com/pdfx/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/photoshop/1.0/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0048_000.js
1c9948fe9ee5fbd379f41504436b2970d8c77dd1aadb8c9d7616ceb0062a1c8a		 pdf-javascript-stream PDF /JS object 48 at offset 0x241F 5443 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 22 eval/decoder/string-building token(s).
polyglot_child_pdf_off00025723.pdf
879559f081deae6090494b3862eb6dbe0b4b71eab0959558c629b5e7eab1cb9f		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x25723 15908 bytes

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