Malicious PDF — malware analysis report

Static analysis result for SHA-256 8620a179a7594642…

MALICIOUS

PDF

118.4 KB
MD5: b44c06950659cdef37324e98ea9fcdd1 SHA-1: 3ba24bbc48856f13a15bf61f9718a2ef66b9496e SHA-256: 8620a179a7594642440f5ed2ab8231bdb996b246f7607f9cd1eedd72a3e0bbfe
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file is a PDF containing embedded JavaScript, which is heavily obfuscated and uses eval() and String.fromCharCode. Heuristics indicate a large comment-padded JavaScript eval stager, and ClamAV identifies it as Pdf.Exploit.Agent-36086. This suggests the script is designed to exploit a PDF vulnerability to download and execute a secondary payload.

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.

FilenameKindSourceSize
javascript_obj0006_000.js
474784fd86d8410ffbbe128d28f9d7ceea7727f4558fbd9021b4fcd6d433d867
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627301 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).