Malicious PDF — malware analysis report

Static analysis result for SHA-256 87983b8045776eef…

MALICIOUS

PDF

68.3 KB Created: 2012-10-02 16:53:23 +04:00 Authoring application: twfnlbx (via phwezws)
MD5: 2855637716a54bfb9edd7b81c2e78301 SHA-1: f55dcebea95197322cb9d15a0e3e9a657655fc12 SHA-256: 87983b8045776eef70be9dff09c07959a29ea7595e7353104ee02e1f1eea39a6
92 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

This PDF contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier strongly flagged this as malicious. The JavaScript is obfuscated, as suggested by the PDF_UNESCAPE firing and the 'Script obfuscation indicators' static triage signal. The extracted JavaScript files, 'javascript_obj0106_000.js' and 'javascript_obj0106_001.js', are the primary indicators of malicious activity. The script's likely intent is to download and execute a second-stage payload, a common technique for malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 6

  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • 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.
  • PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE
    PDF has 1 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
  • 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/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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0106_000.js
4d9d37221f760732af720d3322c69b15c6b9deb625df172477b32599b448f092		 pdf-javascript-stream PDF /JS object 106 at offset 0x10F86 205 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
javascript_obj0106_001.js
f2e81e0072a7fef9b39d7d3618dc28582386b9787a1d9b52f5a0b1a800d84f12		 pdf-javascript-stream PDF /JS object 106 at offset 0x10FA7 366 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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