Malicious PDF — malware analysis report

Static analysis result for SHA-256 712c4c41c356a5a1…

MALICIOUS

PDF

146.3 KB
MD5: ed006c94a604e8b038c4322bc450af26 SHA-1: d02ff3d4fd363dbe4707f3c83a673be01715eacd SHA-256: 712c4c41c356a5a1113507b4f9da66772a5ff7b225bec7a3f1dbd015f29a5363
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 uses a custom base64 decoding function. The script is designed to execute arbitrary code, as indicated by the 'PDF_JS_EXPLOIT_CLUSTER' and 'PDF_UNESCAPE' heuristic firings. The decoded content of the JavaScript, though truncated, suggests it attempts to download and execute a secondary payload. The presence of XFA forms and the use of unescape() are common indicators of PDF exploits.

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
e493bfdb1162d16c10f7ec2daf3808c11f6d6a98d091a0b51f09d9eb1e056463
pdf-javascript-stream PDF /JS object 13 at offset 0x10531 27317 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
javascript_obj0013_001.js
ffc0fbffd340d68591903a8f243d4534de8cbde43395f51038759060ce0f9f93
pdf-javascript-stream PDF /JS object 13 at offset 0x1056D 27325 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