PDF malware analysis — malicious · c8daa65f2efc7e34

MALICIOUS

PDF

15.7 KB

MD5: a538cc9ad188841719bbddf0cbe94d78 SHA-1: c1ebda5ecf7c503605bfdda2334c4c0563a2cdb1 SHA-256: c8daa65f2efc7e3406cbfcbd9a95b92cea55da301bdd8c93053bfb800783f01d

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript

The PDF file contains multiple embedded JavaScript streams, with high-confidence heuristics indicating the use of eval() and a large comment-padded eval stager. ClamAV also detected this file as 'Pdf.Exploit.Agent-36086'. The embedded JavaScript, particularly 'legacy_pdfkit_stage_000.js', is heavily obfuscated but its structure suggests it is designed to download and execute a second-stage payload. The presence of JavaScript actions and embedded JS streams points to a common PDF-based exploit delivery method.

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` `ba18fe82263a89564fd77ecc40839e3670f344b1d4c2b912001a29c8189b3f3d`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	425115 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` `1870099e7bf4ca88db79ae2b957d733d3b9e4c544030cabb0322c9fe38cfad6a`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 560 long base64-like blob(s).

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