PDF malware analysis — malicious · 4b9bb570332a2a89

MALICIOUS

PDF

118.6 KB

MD5: b9f12a439fab8ce3f1059b63139ecd42 SHA-1: 186c483f9d5b9d677b3a4ad2fd5530ceb4208618 SHA-256: 4b9bb570332a2a89726b8b36e76a4b59ad1784467b223aafbffee5846d618d1c

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File T1566.002 Spearphishing Attachment

The PDF contains embedded JavaScript, including a large comment-padded eval stager, which is a common technique for obfuscating malicious code. The presence of `eval()` and `String.fromCharCode` strongly suggests the script is designed to decode and execute arbitrary code. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature, indicating it likely exploits a vulnerability within the PDF reader to achieve its objective, such as downloading a secondary 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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0006_000.js` `7a33d260f5929baea92b5b2b86ea024da602d03846900e5b680fa8b750d7dc85`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626437 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).

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