Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9b69c42420b9b04…

MALICIOUS

PDF

1.63 MB Created: 2008-03-17 20:57:44 +08:00 Authoring application: PScript5.dll Version 5.2 (via Acrobat Distiller 7.0 (Windows))
MD5: f27b828df1b1a95089ed56bc5687dbf9 SHA-1: 48a8026aa83c721ca3c56db6460699dfe137ad1e SHA-256: b9b69c42420b9b046b25c67949c1ff968d8b52ffa68280684acbfef349558c36
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious Link T1566.002 Spearphishing Attachment

This PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The critical CVE-2007-5659 heuristic specifically points to the use of the Collab.collectEmailInfo method, a known vulnerability in older PDF readers. The ML classifier also strongly flagged this PDF as malicious. The embedded JavaScript is likely used to exploit this vulnerability, potentially leading to the download and execution of a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 9

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (matched in decompressed stream)
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PermissionError. 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.
  • 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/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0020_000.js
d88304ff41fbe9077d36e3f5110f2cb08ea62e719e51eaa79078354cdfd84ac8		 pdf-javascript-stream PDF /JS object 20 at offset 0x19F084 4898 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).

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