Malicious PDF — malware analysis report

Static analysis result for SHA-256 ff81960304cdf2a3…

MALICIOUS

PDF

118.6 KB
MD5: 8f323bf7deb22f9a427b9ccd2a36f05b SHA-1: 04a21e754ffff08779d70ead9a8be8e8f524cbe6 SHA-256: ff81960304cdf2a32db52790455743fa4bb16d2ac02be6ebb5e557df13e7e849
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, including a large comment-padded eval stager. Heuristics indicate the use of eval() and String.fromCharCode, common techniques for obfuscating malicious JavaScript. ClamAV detection as 'Pdf.Exploit.Agent-36086' strongly suggests exploitation of a PDF vulnerability to deliver a payload. The exact nature of the payload is not discernible from the provided evidence, but the presence of obfuscated JavaScript points to a downloader or exploit execution.

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
a3d0a5aaed6c35d67a33582c5c259539b1bdead5120ddb57c63f54d1479c50fd
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627216 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).