MALICIOUS
224
Risk Score
Malware Insights
MITRE ATT&CK
T1059.007 JavaScript
T1566.001 Spearphishing Attachment
T1203 Exploitation for Client Execution
The PDF sample contains obfuscated JavaScript that utilizes `unescape()` and `eval()` to execute arbitrary code. The script attempts to deobfuscate and then execute a payload, likely a second-stage downloader. The ML classifier strongly indicates maliciousness, and the combination of JavaScript execution and exploit cluster heuristics points to a common PDF exploitation technique.
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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eval() call high PDF_EVALeval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
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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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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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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
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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.
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
javascript_obj3332_000.jsa105524e6b35a3c7073fa1b7ddac1213d09b678be79c3d2a6932bf8e2a597a30 |
pdf-javascript-stream | PDF /JS object 3332 at offset 0x5AB5 | 312 bytes |
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Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 4 eval/decoder/string-building token(s).
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