PDF malware analysis — malicious · c371bf5eeb2fdf63

MALICIOUS

PDF

118.5 KB

MD5: b33377a3b2e589c2672f35aa5244b17d SHA-1: c1df41948a1c0a6d1029d3bc7caf11d5cfac2fde SHA-256: c371bf5eeb2fdf632bdf0a4dc53456c46fce4efd85233acc0db791c17c9fedb2

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded JavaScript, with high-confidence heuristics indicating the use of eval() and a large comment-padded JavaScript eval stager. ClamAV detection as 'Pdf.Exploit.Agent-36086' strongly suggests exploitation of a PDF vulnerability to execute malicious code. The embedded JavaScript is likely responsible for downloading and executing a second-stage payload, although the specific payload and its destination could not be determined from the provided evidence.

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` `af03901b941f3f9aa5db3c0b486dbe0252d0e9f3b70a91d88230fd230d025b89`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626393 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` `1083a381b18611d808b26451d20e813c7b030d23860a7800c3923a3a67c21bdf`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 467 long base64-like blob(s).

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