Malicious PDF — malware analysis report

Static analysis result for SHA-256 2ed89a2eb6dbcd0f…

MALICIOUS

PDF

118.5 KB
MD5: 91359fe5bc6506040e2d5441b4588774 SHA-1: 835c8eb02ab0edc8f8b58e30d2d5212d108c66bd SHA-256: 2ed89a2eb6dbcd0f62f38f32a213f902d05cb24f894192ff13f2c1f6343da449
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1204.002 Malicious JavaScript

The file is a PDF containing embedded JavaScript, which is heavily obfuscated and uses eval() and String.fromCharCode. Heuristics indicate a 'Large comment-padded JavaScript eval stager', suggesting the script is designed to deobfuscate and execute further malicious code. ClamAV detection confirms this as a known exploit. The primary function appears to be the execution of a malicious script, likely for payload delivery.

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
b9842bcf6b3596b932d73347f92d42a49d30ee635abaa1277a8d5c7b55704611
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626753 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).