Malicious PDF — malware analysis report

Static analysis result for SHA-256 2a5f691db7d59238…

MALICIOUS

PDF

4.1 KB
MD5: 0975c188011c5bf705c22694d7845322 SHA-1: 5f46b6ea857f785097ce041840f7b76f8101ae2d SHA-256: 2a5f691db7d59238cb7b103a4925c18d5b1c24896a94fd22ee59f640980b11bd
156 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes the 'util.printf' function, a known indicator for the CVE-2008-2992 exploit. The JavaScript is heavily obfuscated and appears to decode further layers of code, ultimately aiming to execute a malicious payload. The ML classifier strongly indicates malicious intent. The primary attack vector is likely the exploitation of a vulnerability within Adobe Reader to achieve arbitrary code execution.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • 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)
  • 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.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_001.js
06324865f0c72d1942ea67e0f6415f37b6413dd898d941e2763d6fad980a21c4
pdf-javascript-stream PDF /JS object 13 at offset 0x368 6397 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
acroform_b64_00.js
95144eb7366a1fb52df8397ca363a03307dde186887560b56399ba4305977cba
deobfuscated-js PDF AcroForm base64 (decompressed) at offset 0x99D 3643 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
custom_b64_stage_000.js
85fe71200c33f398824631ccde606ec4fbbce8035fb8611c145accabab2137e1
deobfuscated-js custom Base64 decoded JavaScript layer 2 (PDF /JS object 13) at offset 0x95E 2025 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).