PDF malware analysis — malicious · 4f81975c41c7b85d

MALICIOUS

PDF

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

MD5: 6aa85c43fc77d506b2dd7e1a8b319469 SHA-1: 39306c9d3b77e888b545e967e7644c586d86e6db SHA-256: 4f81975c41c7b85d7840c69ca715f9990cf8208a597e686f223336516459b332

66 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 Command and Scripting Interpreter: PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The presence of a high-confidence PDF_EVAL heuristic firing suggests that the JavaScript is being executed, likely via an eval() call. The extracted artifact 'javascript_obj0001_000.js' further supports the presence of JavaScript code. The use of String.fromCharCode, as noted by the PDF_FROMCHARCODE heuristic, is a common obfuscation technique in malicious JavaScript. The overall pattern suggests the PDF is acting as a dropper for a malicious script, which is designed to download and execute further payloads.

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` `9c8a5e2febed3baa32427b583db1a8dea6cc9ab619fb1bfb26db7efde00d160c`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	902 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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