Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8cbe357943a687b…

MALICIOUS

PDF

15.7 KB
MD5: d20717f7918a8c540b88575a18191eb5 SHA-1: 0bb6a0c65a058bb55de340ea28ec31669fa0c143 SHA-256: f8cbe357943a687bd6992520fe0e1626b481bca8b9b152a9cee8dfa0752fabb8
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file is a PDF containing embedded JavaScript, as indicated by multiple PDF_JAVASCRIPT and PDF_JS heuristics. The presence of a high-severity PDF_EVAL and PDF_JS_LARGE_COMMENT_PADDED_EVAL firing suggests the JavaScript is obfuscated and designed to execute arbitrary code. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The embedded JavaScript stream, named 'javascript_obj0006_000.js', is the primary artifact likely responsible for downloading and executing a secondary 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
15da959f5c8de46a1f5c2c29d4e8e9da73db4a05ba1d3f2b324fd3755ebd455e
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425976 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).