PDF malware analysis — malicious · 6c1c6d186e4e415c

MALICIOUS

PDF

22.6 KB

MD5: 2f0c803a2529882823da7306132cde73 SHA-1: fcc4a2b6e463272c2b53ebedcc327a6bc18d82b1 SHA-256: 6c1c6d186e4e415ccc1b18bad1efc5ed5b22955046efdac2881d6197530498fe

224 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF file contains obfuscated JavaScript that utilizes `eval()` and `unescape()` functions, indicating an attempt to execute malicious code. The script likely downloads and executes a second-stage payload, as suggested by the PDF JavaScript exploit cluster heuristic and the ML classifier's high confidence. The `hK` variable contains the string 'var EnqVjQ = this.subject.replace(/@/g,String.fromCharCode(37));eval(unescape(EnqVjQ));', which is then executed.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 9

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)
ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX

Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
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)
ASCII85Decode filter (with exploit indicators) low PDF_FILTER_85

ASCII85 encoding filter present alongside exploit delivery indicators — uncommon outside of obfuscation
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_obj3332_000.js` `e6614c6c268ebf6c00969675a0789fa767b85f13cc344a5c5782c7739004cd30`	pdf-javascript-stream	PDF /JS object 3332 at offset 0x584D	182 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).

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