Malicious PDF — malware analysis report

Static analysis result for SHA-256 e02d32f602cb341f…

MALICIOUS

PDF

174.9 KB Created: 2008-08-19 23:58:52 -08:00 Authoring application: Acrobat Editor 8.0 (via Adobe Acrobat 8.0)
MD5: ac47898c94c7917d40f076d607b0948a SHA-1: 9bdc1b35e13efeb2af2dfe5359f6189b86ce1097 SHA-256: e02d32f602cb341f1e9565ab4ed0978da15e4fcc3db0bf4f96981a5517bc7c30
148 Risk Score

Malware Insights

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

This PDF file exhibits multiple high-severity heuristic firings related to JavaScript execution and exploit stage recovery. The embedded JavaScript streams, particularly 'generic_stage_recovery_000.js', indicate a sophisticated attempt to exploit a PDF vulnerability. The ML classifier strongly flags this PDF as malicious. The primary function appears to be the execution of obfuscated JavaScript, which likely attempts to download and execute a further payload, a common technique for initial access.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 10

  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, or hex literals. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser exited 1. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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.
  • ClamAV scan did not complete on extracted artifact info CLAMAV_SCAN_INCOMPLETE
    ClamAV did not complete on 2 carved artifact(s); EXTRACTED_FILE_CLAMAV may be missing for this run. The result is not cached so a later submission will retry the scan.
  • 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_obj0032_000.js
b07b17f74b11bbad0eeb9a4da9b550019465b5ddd2c0124614c5dfbb85408162		 pdf-javascript-stream PDF /JS object 32 at offset 0x7E0 3912 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
generic_stage_recovery_000.js
f1303f5d2eae3c56fbf8d2c8977c7d9be9865e6c41554ee1a364bf07b80bdf1f		 deobfuscated-js generic stage recovery percent-decode from JavaScript object 32 at offset 0x7E0 3708 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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