Malicious PDF — malware analysis report

Static analysis result for SHA-256 7af3c5d469e146d0…

MALICIOUS

PDF

118.7 KB
MD5: 48bed6e657ab2c0bc9abb8f70f2687a4 SHA-1: 731ff45f5c2b3cde69091a5122ec1021a1a2c2f3 SHA-256: 7af3c5d469e146d0a2c000706a0c04429b36d01b7e261aa8ceb3e6ca8977755d
166 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript with multiple obfuscation techniques, including `eval()` and `String.fromCharCode()`, as indicated by the 'PDF_EVAL' and 'PDF_FROMCHARCODE' heuristics. The 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' heuristic further suggests a stager pattern. The ClamAV detection 'Pdf.Exploit.Agent-36086' confirms its malicious nature. The primary IOC is the extracted JavaScript file, which is likely responsible for the malicious behavior.

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
2bd152a5070ad00296f4c78e5a5da500638ffbd23204c60df999df378c935a69
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627473 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).