Malicious PDF — malware analysis report

Static analysis result for SHA-256 e8f106d0944f6c93…

MALICIOUS

PDF

15.7 KB
MD5: 009a9cdacb81ff03b6383b0b9ff3bde1 SHA-1: 9fabc4eeecd3c4dc7b0968bd8d8f7119930d17f5 SHA-256: e8f106d0944f6c93f40ca269b9d7fc0f9c626b0876c3ce53b795bf7a2bb81969
166 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The presence of a 'Large comment-padded JavaScript eval stager' heuristic firing, along with ClamAV detection as 'Pdf.Exploit.Agent-36086', strongly suggests the file is designed to exploit a PDF vulnerability and execute a malicious payload. The exact nature of the payload is not clear from the static analysis, but the techniques used are consistent with exploit 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
19c6b80fd0f1f09b9cb7b931b89d00b39c8c4cf750491744ca2b372087d98f4d
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425156 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).