PDF malware analysis — malicious · 531407f565746de3

MALICIOUS

PDF

15.7 KB

MD5: 8b39ca6cb64e5a0d70f85389bf188239 SHA-1: f0bb7ab24482abf9ecdae6c2805418ff3d7e2b7e SHA-256: 531407f565746de3dcc9891018daed5fd751cce313ab74b551e1b651f208dd09

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

This PDF file contains embedded JavaScript, including a large comment-padded eval stager. The JavaScript is heavily obfuscated and uses String.fromCharCode and eval() calls, indicating it is designed to execute arbitrary code. ClamAV detection confirms this is a malicious PDF exploit. The primary function appears to be the execution of a malicious payload via JavaScript.

Heuristics 7

ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL

PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
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_obj0006_000.js` `8fb2f72e63437081af3cded160e768500c532e751b28b68375b4fbead8e3b7bf`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	425648 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).
`legacy_pdfkit_stage_000.js` `e546a9171f32e19f4ef3999fa60c67adfabd3f26d154d7dd9f5ac9c68d9a1f74`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 587 long base64-like blob(s).

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