Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb5bf86bcec991fe…

MALICIOUS

PDF

118.6 KB
MD5: 414a1372c7caf29cf4d0dfaf126b5a70 SHA-1: 304716e58ba4f74d2c3aa2ad0c0cebaba88ed1eb SHA-256: cb5bf86bcec991fe04900c3ecb2d68ee5112a6598f7bafd24c145847237151b3
166 Risk Score

Malware Insights

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

The file is identified as a malicious PDF by ClamAV with the signature Pdf.Exploit.Agent-36086. Static analysis revealed embedded JavaScript streams, including a large, comment-padded JavaScript eval stager. This indicates the PDF likely contains an exploit designed to execute arbitrary code, potentially downloading a second-stage 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
668b787f2fac952061ba399db0e695d5b38e03ba41f5989588a2ca1f25508ce5
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627444 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).