Malicious PDF — malware analysis report

Static analysis result for SHA-256 c0b63598a655acc7…

MALICIOUS

PDF

15.7 KB
MD5: b42d953b4e92de9c62d77d3434c228d1 SHA-1: 74d1b6ad1324cb8035e338d741129e9aa3785838 SHA-256: c0b63598a655acc7502b09446f0c4cdcc98f10ae2bdab58a02ef0538af2afac3
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The critical ClamAV detection of 'Pdf.Exploit.Agent-36086' strongly suggests exploitation of a known PDF vulnerability. The presence of JavaScript streams and the 'Large comment-padded JavaScript eval stager' heuristic point to a downloader or exploit dropper. The extracted file 'javascript_obj0006_000.js' is likely the payload or part of the exploit chain.

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
83c22a145f87c5c3bd79de9c83001beb84679bd7f51a7f0bb92d005463ccca30
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425730 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).