Malicious PDF — malware analysis report

Static analysis result for SHA-256 42b6790424e18c26…

MALICIOUS

PDF

147.5 KB
MD5: ba6cf170c125f3abb361655441cc30bf SHA-1: d42b82d581eab7693413f76e5a7b64e46e6d3cba SHA-256: 42b6790424e18c26bc1e28bcf647371d20231154034ec113bfcfcd9c0690f94f
176 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

This PDF sample was flagged as malicious by ClamAV (Pdf.Exploit.Agent-36189) and a machine learning classifier. Heuristics indicate the presence of embedded JavaScript with unescape calls and ASCIIHexDecode filters, suggesting an attempt to obfuscate malicious code. The ML classifier's high confidence score and the ClamAV detection strongly suggest an exploit is present. The embedded JavaScript stream, named 'javascript_obj0013_000.js', is likely responsible for executing the exploit, potentially downloading a second-stage payload from the unknown-reputation URL http://www.bitstream.com.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 8

  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_000.js
cc820fd8948ae5b45f4321fc9fe4be8e8fbbe1b5bf1edeb22227abb3af32b4fa		 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).
font_00_sfnt_off00000352.bin
a8f4d9b7d604c3c8a0bf3f9a31b9e952d467f98d118fdc784d95d689a14d8a33		 pdf-font-stream PDF embedded font (sfnt) at offset 0x352 65932 bytes

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