Malicious PDF — malware analysis report

Static analysis result for SHA-256 43f098e6a7788665…

MALICIOUS

PDF

5.4 KB Created: 9252-15-54 91:57:08 -19:54 Authoring application: Acrobat Editor 8.0 (via Adobe Acrobat 8.1.0)
MD5: b002048187b01715ff1662e4ae658e33 SHA-1: b1524311fa6fcf9539d129d1601fb000252e0129 SHA-256: 43f098e6a77886650bcb90114767d74eb255e5e93033323439ab585f87294c61
246 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode(), indicative of obfuscation. Critical heuristics identify CVE-2008-2992, specifically the util.printf function, which is used to decode and execute a malicious Adobe Reader exploit stage. The embedded JavaScript is designed to download and execute a second-stage payload, as indicated by the ClamAV detection signature 'Pdf.Exploit.Agent-35551'.

Heuristics 9

  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35551 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35551
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (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.
  • 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)
  • 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_obj0028_000.js
a817a5a40febe6d525b3e2e395cccaf2d5d662c99fbabba8407d1bf2cfbcf00f		 pdf-javascript-stream PDF /JS object 28 at offset 0x4CF 3547 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35551
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
custom_b64_stage_000.js
c9cd64fc2404e05261db0f2627ef0ca951f69d8e8f6086f11b29a4fc2567a4ef		 deobfuscated-js custom Base64 decoded JavaScript layer 1 (PDF /JS object 28) at offset 0x835 2001 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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