Malicious PDF — malware analysis report

Static analysis result for SHA-256 e4f21d97c3e71279…

MALICIOUS

PDF

24.1 KB
MD5: 7559e5b05c688e1c2a0dc51f07b620bf SHA-1: d9fa5f0c4cddbb92a35ae1856c7ec2403234dedd SHA-256: e4f21d97c3e71279d1f87e6d661f84a3fb0b599850b11df32389d49a9995c817
268 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1059.007 Command and Scripting Interpreter: JavaScript/TypeScript

The PDF file contains XFA (XML Forms Architecture) data which is known to be a vector for exploits. Specifically, the CVE-2010-0188 heuristic indicates a vulnerability in Adobe Reader related to LibTIFF and XFA forms. The embedded JavaScript stager, recovered as xfa_numeric_stage_000.js, is likely responsible for downloading and executing a second-stage payload, as suggested by the ClamAV detection 'Js.Exploit.HTML-30' and the 'Suspicious extracted artifact' heuristic. The embedded URL is likely part of this malicious chain.

Heuristics 7

  • Adobe Reader LibTIFF XFA image exploit — CVE-2010-0188 critical CVE likely CVE_2010_0188
    PDF contains the CVE-2010-0188 exploit template: XFA JavaScript heap-spray setup, a generated TIFF image payload, and assignment of that TIFF data to an XFA image field rawValue to trigger Adobe Reader's LibTIFF parser.
  • ClamAV: Js.Exploit.HTML-30 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Js.Exploit.HTML-30
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • XFA numeric JavaScript stager high PDF_XFA_NUMERIC_JS_STAGER
    PDF XFA script reconstructs a hidden JavaScript stage from numeric field data or a character table, then evals the result. The decoder is gated on XFA script, numeric staging, and recovered exploit-like JavaScript or shellcode markers.
  • Suspicious extracted artifact high 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.
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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.xfa.org/schema/xfa-template/2.5/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xfa_numeric_stage_000.js
c50cc87fc3936c5080ce9962def293468d52c6b308cda7ee0acdc1654a5cb3e6
deobfuscated-js XFA rawValue numeric decoded JavaScript (raw) at offset 0x3A8 3735 bytes
Detection
ClamAV: Pdf.Exploit.Agent-36962
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s). Carved artifact contains 3 long base64-like blob(s).