MALICIOUS
242
Risk Score
Malware Insights
MITRE ATT&CK
T1059.007 JavaScript
T1203 Exploitation for Client Execution
T1566.001 Spearphishing Attachment
The PDF file contains obfuscated JavaScript that attempts to exploit a vulnerability. The script uses `unescape` and `String.fromCharCode` to decode a payload, which is then executed via `eval`. This indicates the PDF is designed to download and run a secondary malicious component.
Machine Learning
- Nyx PDF Classifier malicious score 1.0000
Heuristics 9
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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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unescape() call high PDF_UNESCAPEunescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
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Embedded script payload in PDF stream high PDF_EMBEDDED_SCRIPT_PAYLOADPDF stream bytes contain script execution markers such as ActiveXObject/CreateObject, WScript.Shell, PowerShell, or shell-exec primitives. This is stronger than ordinary PDF JavaScript because it indicates a staged external script payload hidden in stream bytes.
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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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Suspicious extracted artifact medium 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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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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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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ASCII85Decode filter (with exploit indicators) low PDF_FILTER_85ASCII85 encoding filter present alongside exploit delivery indicators — uncommon outside of obfuscation
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
javascript_obj3332_000.js887984c392a4f4c24408a1bf6a17e81fd94c86b314787a6fa396770180561b80 |
pdf-javascript-stream | PDF /JS object 3332 at offset 0x5B65 | 422 bytes |
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Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 1 shell/COM execution token(s). Carved artifact contains 3 eval/decoder/string-building token(s).
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