Malicious PDF — malware analysis report

Static analysis result for SHA-256 67436e0a0dda6345…

MALICIOUS

PDF

535.3 KB
MD5: 63d2f1f057975d395d98de7769b4817f SHA-1: e2e63802846ef9fe4808218b99fe8ebd9df38f1f SHA-256: 67436e0a0dda6345d277b419e5f60443acec7ef032f278fce984edf3d7b1cd25
154 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 obfuscated and attempts to exploit vulnerabilities. The ML classifier strongly indicates maliciousness. The JavaScript is designed to download and execute a second-stage payload, likely from the unknown reputation URL http://www.bitstream.com. The presence of XFA forms and JavaScript actions points to exploitation for client execution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9926

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.
  • 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
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules.
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xfa/promoted-desc/
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/
    • http://www.xfa.org/schema/xfa-locale-set/2.7/
    • http://www.xfa.org/schema/xfa-locale-set/2.6/
    • http://www.xfa.org/schema/xfa-form/2.8/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0029_000.js
80d7888ecf9ad9e4d03cd8cc6959f589c8f8783f37d48bb4d7dae53f6684c595		 pdf-javascript-stream PDF /JS object 29 at offset 0x1E2A 8603 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
stream_002_off00000a8f.js
672d461752be4a970c8e9721164ce074d252b55d09d46cc09259d2ce4fc09f7f		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0xA8F 1546 bytes
stream_003_off00000d4c.bin
29cf1edfedd4f27f3c450646c5dc2510e6bf9e63eee1cd436ac517a465a2e1bf		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0xD4C 1650 bytes
stream_004_off000010bc.bin
0f910ffeec733940f6ba1ae41dc6770eab5d615c05bccc95197878b62c8dc45f		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x10BC 2928 bytes
stream_006_off00001651.bin
4a60a9864cdf7382475d51051a03fdc43b32c31eb508893ccfccece34957f9f1		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1651 56 bytes
stream_007_off000016d9.bin
fe122a09d8a0444608fdc5a6f4981a2dbd469f5bbfacb4bdd327c28ccc343e13		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x16D9 149 bytes
deobfuscated.js
da23701ff41739692b5a771745e596899593b5eb3d59ed1492d9e193b07660bd		 deobfuscated-js PDF JavaScript deobfuscation pass 2863259 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 16 long base64-like blob(s).
font_00_cff_off00004aaf.bin
ea8f409c7366ed46eeb553aa7b404f04641f482ba88463fbe253da60be5787e5		 pdf-font-stream PDF embedded font (cff) at offset 0x4AAF 1138 bytes
font_01_sfnt_off000054a2.bin
e31f8c8507e52f29008d946a00becde9f839e34cb108985ce66167bf881adafa		 pdf-font-stream PDF embedded font (sfnt) at offset 0x54A2 8084 bytes

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