PDF malware analysis — malicious · d59c98ac3ae5e7be

MALICIOUS

PDF

118.6 KB

MD5: f0f98748e09421d92b1fcd9c0985f60a SHA-1: 19a285e6b81be34159c040e5dc119d754bb8ea6f SHA-256: d59c98ac3ae5e7bee9702f60c4ce02dae16beed8962c2bfbac9678a00d345338

196 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript T1204.002 Malicious File

The PDF contains embedded JavaScript, including a large comment-padded eval stager and multiple calls to eval() and String.fromCharCode(). These heuristics, combined with ML classification and ClamAV detection (Pdf.Exploit.Agent-36086), strongly indicate malicious intent. The primary function of the JavaScript appears to be the execution of a secondary payload, typical of exploit-based PDF documents.

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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0006_000.js` `a5d06d48efc4bbccf2a3cb99a1990393bcad8b9760cf65d412fe384f3d96ffb2`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	627625 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` `2da9cd96cd8b5f4076ff2b93aea81c8922da6d52f8d0525ed0b7cc22797397cf`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 655 long base64-like blob(s).

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