PDF malware analysis — malicious · 5efde1278cbde9aa

MALICIOUS

PDF

2.1 KB

MD5: 851eba6c593a71c5e075c9ca09423962 SHA-1: 93750f345e768f336f857b7fc8768ee15d3615ab SHA-256: 5efde1278cbde9aa9baac9fe576ccc98b958c386e7af7a375373a8f66356b53b

196 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains obfuscated JavaScript, indicated by the PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL heuristics. The script utilizes `eval()` and `unescape()` with `String.fromCharCode()` to deobfuscate and execute code, a common technique for downloading and running secondary payloads. The ML classifier strongly flags this PDF as malicious, supporting the conclusion that it is designed for exploitation.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 7

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.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
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.
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. (matched inside decoded stream)
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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj111611_000.js` `9864171cc4152f5d3e5671809dd40cebe1cf9319d0b8bfb0abd003cff50482db`	pdf-javascript-stream	PDF /JS object 111611 at offset 0x766	332 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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