PDF malware analysis — malicious · 79c52fd65366cb78

MALICIOUS

PDF

118.5 KB

MD5: 534138cab835eb486673024f4095bdeb SHA-1: 04a2b5549cf4e5978ab88aa9bf4bd3b85e3ddba6 SHA-256: 79c52fd65366cb78aba463f9c3897ba062f096766e9a12928e8b17e9a5df90bd

166 Risk Score

Malware Insights

MITRE ATT&CK

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

The file is identified as a malicious PDF by ClamAV. Static analysis reveals embedded JavaScript with multiple obfuscation techniques, including `eval()` calls and `String.fromCharCode`, strongly indicating an attempt to execute arbitrary code. The presence of a large comment-padded JavaScript eval stager further supports this. The primary function of the embedded JavaScript appears to be downloading and executing a second-stage payload, as suggested by the heuristic firings and the nature of such exploits.

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` `53d629753f6b2166d4047e37d46f1ee1fcbb85ab6fe0933d232da7306c2504ac`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626685 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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