PDF malware analysis — malicious · 91661cb9092ef5a7

MALICIOUS

PDF

118.5 KB

MD5: ef5637733514a3a17beda1a1c3692aaa SHA-1: 602a4d64ce3e4bb0a6d664e9705241cd4620ce32 SHA-256: 91661cb9092ef5a72619603831f7d3fe11c392a692177b503417535d467af716

196 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF sample was flagged by multiple high-severity heuristics, including PDF_EVAL and PDF_JS_LARGE_COMMENT_PADDED_EVAL, indicating the presence of obfuscated JavaScript designed to execute arbitrary code. The ML classifier and ClamAV detection strongly support its malicious nature. The embedded JavaScript stream, identified as 'javascript_obj0006_000.js', is the primary mechanism for exploitation, likely serving as a stager for further malicious activity.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

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` `d316e4936d65b974cea79f957afaa83c01d4237728765bb0379960600048f4ec`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626739 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).

Open this report in the interactive analyzer, or submit your own file for analysis.