Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8b663a29c5e147c…

MALICIOUS

PDF

118.6 KB
MD5: 87e8bcd25651082145866ea195f39c52 SHA-1: eb8e7a30e367ad36748cfa3a8b9e00bd0a895ad0 SHA-256: c8b663a29c5e147c3d8d66c68c2b06e032faecac103c3f66d17fe58f1a7e45c4
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious File

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The critical ClamAV detection of 'Pdf.Exploit.Agent-36086' strongly suggests malicious intent. The JavaScript stream, identified as a large comment-padded eval stager, is designed to execute arbitrary code, likely downloading and running a second-stage payload. The document body was unreadable, but the presence of obfuscated JavaScript and the ClamAV signature are sufficient indicators of a malicious exploit.

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
93f55bbf6fd6b07758178928aa0bb1dc10e0869dae598bd3d3296e1184865cd2
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626807 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).