Malicious PDF — malware analysis report

Static analysis result for SHA-256 88135c000bc728bd…

MALICIOUS

PDF

15.7 KB
MD5: 3a2f90368b2b63388924b4df5db3f21a SHA-1: 8c09d4fb8074a2cc4cb98c5c616de5b68e9f7d02 SHA-256: 88135c000bc728bd5848882cbbe962bfd3306c6fad0a65f9ddec482ff5e8531c
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1071.001 Web Protocols

The file is a PDF containing embedded JavaScript, as indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_JS_LARGE_COMMENT_PADDED_EVAL'. The critical 'CLAMAV_DETECTION' for 'Pdf.Exploit.Agent-36086' strongly suggests malicious intent. The embedded JavaScript, identified as 'javascript_obj0006_000.js', likely serves as a stager to download and execute a secondary payload, a common technique for initial access and further infection.

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
dc3c3580563aa753947c9a49d96be96ab4b1365b5b577cccf7d57867ac38cc93
pdf-javascript-stream PDF /JS object 6 at offset 0x143 424992 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).