Malicious PDF — malware analysis report

Static analysis result for SHA-256 6d04443875454107…

MALICIOUS

PDF

118.6 KB
MD5: e1cf67e3d209ab4351cf862b1d8d1921 SHA-1: c61b2294476331f4396a2f720d9933990111422a SHA-256: 6d04443875454107f6485ecbfa078a221b1102a47a162d0c6731151589c6d047
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

This PDF file contains heavily obfuscated JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, PDF_EVAL, and PDF_FROMCHARCODE. The critical PDF_JS_EXPLOIT_CLUSTER and PDF_JS_LARGE_COMMENT_PADDED_EVAL heuristics, along with ClamAV detection as Pdf.Exploit.Agent-36086, strongly suggest it's designed to exploit a vulnerability. The obfuscated JavaScript likely acts as a stager to download and execute a further payload, a common technique for initial compromise via malicious attachments.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
1e1b8285b715d2d0724ab281edb6030593aac9c646643c21f072b8a3b4f55170
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626329 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).
stream_002_off0001d88e.bin
26b60607985ad31d5014ba7fc7aaa63f3f2d876016b1822b44f8cc1c589a4c2e
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D88E 200 bytes