Malicious PDF — malware analysis report

Static analysis result for SHA-256 43c766aef3d0dfbb…

MALICIOUS

PDF

118.7 KB
MD5: 73d81dd643348b9db43db589a87f6802 SHA-1: 7223b79b2f05ca6bc2ab4550f03261e4fe9ba366 SHA-256: 43c766aef3d0dfbb0c24272d7c1002353a491324c601a9ace23e7332deca93fc
166 Risk Score

Malware Insights

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

The file is a PDF containing embedded JavaScript, which is a common technique for exploiting vulnerabilities and delivering malware. Heuristics indicate the use of eval() and String.fromCharCode, suggesting obfuscated code execution. The ClamAV detection 'Pdf.Exploit.Agent-36086' strongly suggests a known exploit is present. The embedded JavaScript stream, although large and potentially obfuscated, is the primary mechanism for exploitation, likely leading to the download and execution of a second-stage payload.

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
3cbd99e34e863d0871f7608a36ab344382d64dfbfe1002a4b923b23f982f8b31
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627827 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).