PDF malware analysis — malicious · 4c163eaa9bf4255d

MALICIOUS

PDF

118.6 KB

MD5: c3d679312770a4219fd1f60299aea670 SHA-1: 2aca4693a1407579b7ca15ffa2237cb13c8e5e0f SHA-256: 4c163eaa9bf4255d9866478f9b690244fdbb034061b1fc5afd0c27b3606cff48

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/Scripting T1204.002 Malicious Link/URL

The PDF contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The presence of 'Large comment-padded JavaScript eval stager' and 'Suspicious extracted artifact' with 'Script obfuscation indicators' suggests the JavaScript is designed to obfuscate malicious activity. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The primary attack vector appears to be exploiting PDF vulnerabilities to run this script, which likely downloads and executes a second-stage payload.

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` `4ef9a682b1263f5efa2f26b27c6cdecd1cbcba14670c6b555744c95532dae944`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	627193 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` `04e9c15390bd5577e9623d27d268d29588d436b9597c8a84e50220dab0abd5f2`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 518 long base64-like blob(s).

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