PDF malware analysis — malicious · c1a8aff8bb447603

MALICIOUS

PDF

118.6 KB

MD5: 246e2b1b199a0588d9389b3fc448bcf4 SHA-1: d3fb756b536372fb65be0fe35f0247e1c371420a SHA-256: c1a8aff8bb44760349b4027a02fc83d7588cd4bb3cf3968e3293f5bb5594d8e7

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains multiple embedded JavaScript streams, with high-confidence heuristics indicating obfuscated JavaScript and eval() calls. One heuristic specifically flags a 'Large comment-padded JavaScript eval stager'. This suggests the primary function of the PDF is to exploit a vulnerability and execute malicious JavaScript. The ClamAV detection 'Pdf.Exploit.Agent-36086' further supports this, indicating a known exploit within PDF documents. The JavaScript is heavily obfuscated, making it difficult to determine the exact second-stage payload, but the pattern is consistent with exploit-based delivery mechanisms.

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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0006_000.js` `4507680092a639720391ab547773121c7fd6fe819e9fbd28d28f1231f8f5fbc4`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	626789 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` `cd27185e0bfa2acafda6654ad412b79c511c146f1646788417027216bff633e3`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 601 long base64-like blob(s).
`legacy_pdfkit_stage_001.js` `9b07ddd7cd7291e7267b357dbae5cf9b220b6cab9b2c4e3ef755645a868a8e2e`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 443 long base64-like blob(s).

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