Malicious PDF — malware analysis report

Static analysis result for SHA-256 34b8ed2c5f2e7f1e…

MALICIOUS

PDF

118.6 KB
MD5: c144cbbc02daeada3dd049239a45f4d9 SHA-1: 37aa4e40caf8cc9cc6ddb8720d2cce2091b79154 SHA-256: 34b8ed2c5f2e7f1ee80ee4e7bd211685f861a2b8f9cb23a268955104c5ad36de
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains embedded JavaScript, which is heavily obfuscated and utilizes eval() and String.fromCharCode. A heuristic specifically flags this as a 'Large comment-padded JavaScript eval stager'. This indicates the script's primary purpose is to deobfuscate and execute further malicious code, likely a downloader for a second-stage payload. The ClamAV detection 'Pdf.Exploit.Agent-36086' further supports its malicious nature.

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
63016b493df6a06879e3cb4decc03dd8cc2ee7464435a3740a389eac676ea6f6
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627375 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).