MALICIOUS
146
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, but the presence of PDF_JS_EXPLOIT_CLUSTER and PDF_FROMCHARCODE heuristics indicates an exploit attempt. The JavaScript decodes a string which, based on the obfuscation pattern, likely resolves to a URL used to download a secondary payload. The ML classifier strongly flags this PDF as malicious.
Machine Learning
- Nyx PDF Classifier malicious score 0.9998
Heuristics 8
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PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTERPDF 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.
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ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEXHex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
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JavaScript action low PDF_JAVASCRIPTPDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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Embedded JS stream low PDF_JSPDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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XFA form low PDF_XFAPDF uses XML Forms Architecture — can contain script logic
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String.fromCharCode low PDF_FROMCHARCODEString.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. (matched inside decoded stream)
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Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGEOne 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.
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Embedded URL info EMBEDDED_URLOne 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.
| Filename | Kind | Source | Size |
|---|---|---|---|
javascript_obj0013_000.js105dab3a8b22993aeb3e1aa7806c39bbd6559fd4466f8e2bb321007277d506ef |
pdf-javascript-stream | PDF /JS object 13 at offset 0x10531 | 20836 bytes |
|
Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 1 eval/decoder/string-building token(s).
|
|||
font_00_sfnt_off00000352.bina8f4d9b7d604c3c8a0bf3f9a31b9e952d467f98d118fdc784d95d689a14d8a33 |
pdf-font-stream | PDF embedded font (sfnt) at offset 0x352 | 65932 bytes |
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