Malicious PDF — malware analysis report

Static analysis result for SHA-256 76638dee019a9acd…

MALICIOUS

PDF

4.2 KB
MD5: cd1e930c1f94d5a17b56f5c3ae1cc93e SHA-1: f20749cda7723e89548c1bde847b9b96fb91bac8 SHA-256: 76638dee019a9acd770e8fb5a3b847048decc99afad9873357ea9632197dd694
216 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains obfuscated JavaScript that leverages the CVE-2008-2992 vulnerability. The JavaScript uses `eval()` and `String.fromCharCode()` to decode and execute exploit code, likely to download and run a second-stage payload. The ML classifier strongly indicates maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 7

  • 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)
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
7d22b74aba48261b23db6d78dd65e02cce97f01f4015235d7450e8533f482b77
pdf-javascript-stream PDF /JS object 5 at offset 0x107 22806 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
numeric_charcode_stage_000.js
ab4347bc27f8b343108be61489f0a81fdc10698e98839f331dd64c39b83dbfe1
deobfuscated-js numeric char-code string decoded JavaScript at offset 0x115 6700 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).