PDF malware analysis — malicious · 51caf9bff40e7b45

MALICIOUS

PDF

118.6 KB

MD5: 9d2b4f1ff3a27bf35c71d93271f20b92 SHA-1: 6a7a6d4eadcaf06a13082ae102ecc0a6d489dce8 SHA-256: 51caf9bff40e7b450c2a3443ca2afdc06b8b32360e635b14e62da7e94d620f8b

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The presence of a 'Large comment-padded JavaScript eval stager' heuristic firing, along with ClamAV detecting it as 'Pdf.Exploit.Agent-36086', strongly suggests this PDF is designed to exploit vulnerabilities and download further malicious content. The primary attack vector appears to be leveraging JavaScript execution within the PDF viewer.

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` `d965d8d81bdb45d38b4ef0703368eb29dcfbf490e0e3a56c6ca523083f96945c`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626672 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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