PDF malware analysis — malicious · c51b393590593165

MALICIOUS

PDF

118.6 KB

MD5: c1defe26fe803c96d780796a2e16646e SHA-1: 343d4e2275ec6ee15874117a148d6f3f0a932603 SHA-256: c51b39359059316561d7b91a8ad219a5b94c575b196dea03da65e62c709f4bb0

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, including a heavily obfuscated 'eval stager' and calls to String.fromCharCode, indicating an attempt to hide malicious code. ClamAV detected this as 'Pdf.Exploit.Agent-36086'. The primary attack pattern involves exploiting PDF vulnerabilities to run this JavaScript, which is designed to download and execute further malicious content.

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` `7cdad3ebd97a0aca5749f89c4f358f791f2307dbb16637413e6d3c598243b56d`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626841 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` `ff0cf5e21edfb99c8369f0d4e98458b94203686621cd4818752f4101d74551b2`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 614 long base64-like blob(s).

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