Malicious PDF — malware analysis report

Static analysis result for SHA-256 049c67900916f4a2…

MALICIOUS

PDF

146.9 KB
MD5: b39a66567aa07b8426e05eb9765d55a5 SHA-1: 6d828e1b254e5afdfe491586b61c019e235882d9 SHA-256: 049c67900916f4a222b588d076e928e00319df56bdfcbc33f24842564f336a34
238 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that is heavily obfuscated and utilizes a custom base64 decoding function. This script is designed to download and execute a second-stage payload from a remote URL. The critical PDF_JS_EXPLOIT_CLUSTER and PDF_UNESCAPE heuristics, along with ClamAV detection, strongly indicate an exploit attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 9

  • 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-36189 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36189
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • 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.
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.bitstream.com
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_000.js
3e8ac6fb0a346c713cfe05af89c81f40e7de55caacb6e9f88cd83c6f25267fc2
pdf-javascript-stream PDF /JS object 13 at offset 0x10531 27541 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
javascript_obj0013_001.js
594c348ca3e68bc110a86cd8e80c9068e075a400aa2d6de1f3443e02b2249d2f
pdf-javascript-stream PDF /JS object 13 at offset 0x1056D 27549 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
font_00_sfnt_off00000352.bin
a8f4d9b7d604c3c8a0bf3f9a31b9e952d467f98d118fdc784d95d689a14d8a33
pdf-font-stream PDF embedded font (sfnt) at offset 0x352 65932 bytes