Malicious PDF — malware analysis report

Static analysis result for SHA-256 21a8a056fd4aab24…

MALICIOUS

PDF

202.5 KB Created: 2009-06-06 21:05:54 +08:00 Authoring application: Acrobat Distiller 7.0 (Windows)
MD5: c7667c7b3a300b7b1be255c67f1e481c SHA-1: ad971abc1b32134efc79adc39e4f5e40a4a778c8 SHA-256: 21a8a056fd4aab246e10d96356edd872a66b966c75b1728a329f953610de03fe
148 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier and ClamAV detection strongly suggest malicious intent. The unescape() function is often used to deobfuscate malicious JavaScript. The primary function of the embedded script appears to be downloading and executing a second-stage payload, as suggested by the 'javascript_obj0017_000.js' artifact and the ML_NYX_PDF_MALICIOUS score. The ClamAV detection name 'Pdf.Dropper.Agent-7238508-0' further supports this dropper functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • ClamAV: Pdf.Dropper.Agent-7238508-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7238508-0
  • 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.
  • 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/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdfx/1.3/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0017_000.js
b27832c2b4d1bde0d739bb47befc664a0bf9749f03cff2732212758c3e6b2e8b		 pdf-javascript-stream PDF /JS object 17 at offset 0x4D8 5090 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 22 eval/decoder/string-building token(s).

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