PDF malware analysis — malicious · 6c1c0d9b34f1fe14

MALICIOUS

PDF

118.5 KB

MD5: 6555157d68a641ea5e6af2e3aceeb78f SHA-1: 625423687f9a3b4a10ae51ef14121da57aba72a8 SHA-256: 6c1c0d9b34f1fe147b949e406b17409918c563508cb2f2f8f4c4683339915fc9

256 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF file contains obfuscated JavaScript that utilizes eval() and String.fromCharCode(), common techniques for exploiting PDF vulnerabilities and executing malicious code. The presence of 'PDF JavaScript exploit cluster' and 'Large comment-padded JavaScript eval stager' heuristics, along with ClamAV detection as 'Pdf.Exploit.Agent-36086', strongly indicates a malicious exploit. The JavaScript is likely designed to download and execute a second-stage payload, although the specific URL or payload is not directly extractable from the provided evidence.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

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.
ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL

PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0006_000.js` `0e1d6ee468957f2fda000abd0d6011c72378ce150823aa1e6ec7a966eba3ecd3`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626991 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).
`legacy_pdfkit_stage_000.js` `ee4f6aa74b5ec17e07e440cd092768a4134e810e1559cb61bf4f9237f79971fd`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 676 long base64-like blob(s).

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