Malicious PDF — malware analysis report

Static analysis result for SHA-256 f1bd787507189efb…

MALICIOUS

PDF

118.6 KB
MD5: b3137e2e9c2ee99c6159d30269422db6 SHA-1: 0e7010031bf948a4bab42890ae375a632afee5d8 SHA-256: f1bd787507189efb2ac3a43535a4e7f2df1368b365716f118f7f86c3bc2811a4
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.007 JavaScript

The PDF file contains embedded JavaScript, including a large comment-padded JavaScript eval stager. Heuristics indicate the use of eval() and String.fromCharCode, suggesting obfuscated code execution. ClamAV detection as 'Pdf.Exploit.Agent-36086' confirms its malicious nature. The primary attack pattern involves exploiting PDF vulnerabilities to run JavaScript, which is likely used to download and execute further malicious content.

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
c4cf588048c7a9dbaaea1ba39a8823b67496293c9cd7b75860d33e073af90d27
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627365 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).