Malicious PDF — malware analysis report

Static analysis result for SHA-256 9c4455b7d75d77bc…

MALICIOUS

PDF

118.5 KB
MD5: 9768ac74abac96a9d86e9148fcc544ed SHA-1: 97506a45164a3f007fafb0ad2714a99a2aef998c SHA-256: 9c4455b7d75d77bcf0cbcc2907b0a60f5c2192fce57d7f320e28c8b520ab6816
166 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript that utilizes `eval()` and `String.fromCharCode` functions, indicating an attempt to obfuscate and execute 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 this PDF is designed to exploit a vulnerability and download a secondary payload. No document body text was available for analysis, but the script behavior is indicative of a downloader or exploit delivery mechanism.

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
43d2fe6d13481dc1b47a64c450e369fa92f10c52191cbe8b72a77fe5acec8881
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626930 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).