MALICIOUS
158
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 utilizes a Base64-like decoding function, indicated by the `zjjjzjjzs` function and the `unescape` call. This script is designed to deobfuscate and execute further malicious code, likely a second-stage payload. The presence of PDF JavaScript exploit cluster heuristics and ML classification strongly suggests malicious intent. The decoded content is not fully visible due to truncation, but the structure points to a downloader or exploit execution.
Machine Learning
- Nyx PDF Classifier malicious score 0.9998
Heuristics 7
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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
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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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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 3
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
javascript_obj0013_000.jsb34f065679ac9b7a86505d2aef51534dce9e4c19b5c3f69ca696007f109fa573 |
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).
|
|||
javascript_obj0013_001.js31d217eb7125537bc6f88ab6caaab5fe96c37ea045a6cb09863b11f8205b2732 |
pdf-javascript-stream | PDF /JS object 13 at offset 0x10555 | 4878 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.bina8f4d9b7d604c3c8a0bf3f9a31b9e952d467f98d118fdc784d95d689a14d8a33 |
pdf-font-stream | PDF embedded font (sfnt) at offset 0x352 | 65932 bytes |
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