Malicious PDF — malware analysis report

Static analysis result for SHA-256 71eb9c93a2db7bf3…

MALICIOUS

PDF

147.5 KB
MD5: 9e9a0debcd555bd43b1fd2e1e3079d35 SHA-1: 9d90286a32736df431895230b80be978bbf9619d SHA-256: 71eb9c93a2db7bf3887fdb96c03a87db3ca2bfabc7a2aac5a469dcc40f6941a0
238 Risk Score

Malware Insights

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

The PDF sample contains embedded JavaScript that is obfuscated and utilizes an unescape function, indicating malicious intent. The JavaScript is designed to decode and execute further code, likely a payload. The ClamAV detection and ML classifier strongly suggest this is a malicious PDF exploit, with the primary technique being JavaScript execution within the PDF.

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
aaff8372148c1e5d9b9468f676052a84ea07ad0557182fc2da4c3b4eea090636
pdf-javascript-stream PDF /JS object 13 at offset 0x10531 27749 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
javascript_obj0013_001.js
5ab7ccd99d36e3bd4ecb3f63bc3e47c5dcc323668f45ae4cea21b33b7245a3f7
pdf-javascript-stream PDF /JS object 13 at offset 0x1056D 27757 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