PDF malware analysis — malicious · 6f4cb885b2f50988

MALICIOUS

PDF

76.2 KB

MD5: 8de74fdf031da9145a9234e42eca4d59 SHA-1: f8d9c933f8456fbdfa0a6607ac83c317349218a6 SHA-256: 6f4cb885b2f509889dc1ce6163efc35a5a73adc60630eebf15f4afe83f45f7e5

256 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that is heavily obfuscated using binary-XOR encoding and string manipulation techniques. The heuristics indicate this JavaScript is designed to exploit CVE-2007-5659 (Collab.collectEmailInfo) in Adobe Reader. The script's primary function is to decode and execute a second-stage payload, likely for further malicious activity.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

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. (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
Binary-XOR JavaScript stager high PDF_BINARY_XOR_JS_STAGER

PDF JavaScript stores viewer-version payload branches as long binary digit strings, XORs each bit pair, converts 8-bit chunks with String.fromCharCode, and evals the recovered exploit stage.
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.
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.

Filename	Kind	Source	Size
`javascript_obj0004_000.js` `0ae59f6a9acb44968d210581db94ce0d0348c61de03bc73fb3800a28e59cbd4d`	pdf-javascript-stream	PDF /JS object 4 at offset 0xC0	77722 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
`javascript_obj0004_001.js` `92cf4d9e40974cd81a168db21709c0505a3678b14591c713b77e3af24e62febd`	pdf-javascript-stream	PDF /JS object 4 at offset 0xE3	77833 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
`binary_xor_stage_000.js` `1551bcad664ebc238494d26c9cae5bfe9071cd2c66cb998fcf9faec5ae30a211`	deobfuscated-js	binary-XOR decoded JavaScript at offset 0x3D7	1273 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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