Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b87bd1b51fa0fbb…

MALICIOUS

PDF

1.01 MB Created: 2008-03-03 17:06:20 +08:00 Authoring application: PScript5.dll Version 5.2 (via Acrobat Distiller 6.0.1 (Windows))
MD5: 2d2a649d6288a5312500fc07a8e287e7 SHA-1: b5394baf3d7287da79fe40fd99b9c2ba637cf234 SHA-256: 4b87bd1b51fa0fbb330c0dd783ba6b37b5f81b6676376aa3c0e55285daccdcbf
228 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/Shell Scripting: JavaScript T1204.002 Malicious File: User Execution: Malicious File

The PDF file contains embedded JavaScript that is obfuscated and utilizes the unescape() function, indicating malicious intent. The critical CVE-2007-5659 heuristic firing confirms the exploitation of a known vulnerability in Adobe Reader. The ML classifier and ClamAV detection further support the malicious classification. The embedded JavaScript likely downloads and executes a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 10

  • 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)
  • ClamAV: Pdf.Exploit.Agent-35906 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35906
  • 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
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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/xhtml
    • http://www.xfa.org/schema/xfa-data/1.0/
    • 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://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0032_000.js
9180f2c3019e9e7224a234036f90c05e97ddebab395df189c194400a9a4f7553		 pdf-javascript-stream PDF /JS object 32 at offset 0x156B 4622 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).

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