PDF malware analysis — malicious · c1c79fe8ff4c686e

MALICIOUS

PDF

118.5 KB

MD5: bbcfe94b3bdcc65501c4adb97502333c SHA-1: 8126ec3a7673f77d61a833baf21a5c0170bd6a1b SHA-256: c1c79fe8ff4c686e8edc26df6d00f586d54366015520f28c820c4b1b894ce555

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file is a PDF containing embedded JavaScript, which is a common technique for exploiting vulnerabilities in PDF readers. Heuristics indicate the use of eval() and String.fromCharCode, suggesting obfuscated code designed to download and execute a payload. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The extracted JavaScript file is large and exhibits obfuscation, consistent with a stager for a second-stage download.

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` `1317ac814ec77263644a7ebff2db62be3c4e72a97ec82366831b0223cfd444a5`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	627604 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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