PDF malware analysis — malicious · 66f0c986d7fb2903

MALICIOUS

PDF

4.3 KB

MD5: ef2183794a4ec5d9edfb24afbae7aa50 SHA-1: 829e52094915ca601a9798cb8364f250f826e8d4 SHA-256: 66f0c986d7fb2903550c01f4537b1684ab6637eb0a41eb0e14dc155250f03524

216 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that utilizes the `util.printf` function, a known indicator for the CVE-2008-2992 vulnerability. The JavaScript is heavily obfuscated using `String.fromCharCode` and `eval()` to hide its malicious intent, which is to exploit this vulnerability and likely download a secondary payload. The ML classifier also strongly indicated 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.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `97ab801c27ff9a38b6c8b090d21b57c9f789961695770351ab7964d94746eab6`	pdf-javascript-stream	PDF /JS object 5 at offset 0x107	21944 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` `981d9c15cc333489135a0de2ced91f10e62460cb481cfda7d7af528d0cbef759`	deobfuscated-js	numeric char-code string decoded JavaScript at offset 0x115	6465 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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