PDF malware analysis — malicious · 8b9f9158a6c3a7cd

MALICIOUS

PDF

15.7 KB

MD5: 4b56386c5130bd37c2d9f9f3491a14b3 SHA-1: b3a92f48d0f5e173390faf921b57bc76adbc519a SHA-256: 8b9f9158a6c3a7cdbf3a8bcc32045374e791bc7526cb7c89fce1265f8a8145c9

166 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File T1566.002 Spearphishing Attachment

The PDF file contains embedded JavaScript, including a large comment-padded eval stager, indicating an attempt to obfuscate malicious code execution. The presence of `eval()` and `String.fromCharCode` functions strongly suggests the script is designed to decode and execute arbitrary code. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature, likely involving exploit delivery.

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` `00f6121bd489136ae22bffaba287f4417a375171f515cf17fa3d186a57793961`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	425066 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).
`stream_001_off00003b70.bin` `b1c7bec724dacb7fe9c35333e69bbc0cbb3e740ad10070004269465869286347`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x3B70	300 bytes
`legacy_pdfkit_stage_000.js` `a47b1f698b420ac2b20c57c093dcfee200786b322ffc9412596c884277a4c585`	deobfuscated-js	double percent-decoded annotation JavaScript at offset 0x143	262144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 614 long base64-like blob(s).

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