PDF malware analysis — malicious · b41157b65f2e3019

MALICIOUS

PDF

22.4 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode

MD5: 55635981ca59998223ee73ca2c68a9fe SHA-1: 5aafa06357accbf747cc59005f27d0e9c6072e5f SHA-256: b41157b65f2e30192c0d9bb0fcfb17413824b3ded02f6418a81180d6b35c1136

66 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1059.007 Command and Scripting Interpreter: JavaScript/TypeScript

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream utilizes `String.fromCharCode` and `eval()` to execute obfuscated code, a common technique for downloading and executing further malicious payloads. The presence of `eval()` and `String.fromCharCode` strongly suggests dynamic code execution. No specific family could be identified, but the overall pattern points to a downloader.

Heuristics 5

eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
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.
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_obj0001_000.js` `c2df689562a91c1cb3b7a75a5ac0a336b4e58035a93d848de878ba5c0fe39507`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	506 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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