Malicious PDF — malware analysis report

Static analysis result for SHA-256 b826f8511a53026b…

MALICIOUS

PDF

70.1 KB
MD5: fbceec5d796f797e375077bf7ac253ff SHA-1: a497c4912b8d93484b720503637c45ade2e2f62e SHA-256: b826f8511a53026ba28b5d9e87f5f40800c5bf6831d83981890dcbfdcd48a214
96 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious Link T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript, indicated by PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier strongly flags this PDF as malicious. The JavaScript uses an unescape() function, suggesting obfuscation and potential exploitation. The primary intent appears to be downloading and executing a second-stage payload from the embedded URL http://www.bitstream.com, as evidenced by the ML_NYX_PDF_MALICIOUS heuristic and the presence of a suspicious JavaScript file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • 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
daff2173d83feb4735be5bb049b923b6cc9d1aab2b15001790bcfbb1cd93ec1a		 pdf-javascript-stream PDF /JS object 13 at offset 0x10531 3967 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
font_00_sfnt_off00000352.bin
a8f4d9b7d604c3c8a0bf3f9a31b9e952d467f98d118fdc784d95d689a14d8a33		 pdf-font-stream PDF embedded font (sfnt) at offset 0x352 65932 bytes

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