PDF malware analysis — malicious · e23c1a51cb55a958

MALICIOUS

PDF

118.6 KB

MD5: dbc966b161ae72cc06017e409fe2d299 SHA-1: 2e09d119f0a3f91a92aa5c10657fd4879f2b29b2 SHA-256: e23c1a51cb55a9588250d99ae1e601c1aa3e39ce7feda779c87fa301ba4b0660

196 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript T1204.002 Malicious File T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. High-confidence heuristics like 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' confirm its malicious nature. The embedded JavaScript is likely responsible for downloading and executing a secondary payload, a common technique for PDF-based exploits.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 7

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` `0792dc66abe44a54dfa51cfb7b13c9744c5df2682cb67d1b2b4ca8cc0194bcb3`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	627248 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` `290c2ac67f2a47665cda72e69eaa72a7bfcf1beea1069ffdabe1a274f9d84bed`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 540 long base64-like blob(s).

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