PDF malware analysis — malicious · 908736bedfa0abb4

MALICIOUS

PDF

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

MD5: bb093a175f59c8c81788491cc857ac5f SHA-1: 1cf6b407db474ca536e8a54495c3817655e18d64 SHA-256: 908736bedfa0abb415dfd83d0a068c68b59b602847fb7f181152c8e03e46b883

136 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, flagged by multiple heuristics including PDF_JAVASCRIPT, PDF_JS, and PDF_METADATA_EVAL_STAGER. The high-severity PDF_EVAL heuristic indicates that obfuscated JavaScript code is being executed. The ML classifier strongly suggests maliciousness. The extracted artifact javascript_obj0001_000.js is a JavaScript file, likely containing the payload. The script's purpose is to download and execute a second-stage payload, as indicated by the 'eval()' call and the stager heuristic.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
PDF metadata JavaScript eval stager high PDF_METADATA_EVAL_STAGER

PDF JavaScript reads document metadata fields such as title, subject, or producer, decodes character data with parseInt/String.fromCharCode style helpers, and evals the recovered stage. This is a high-signal exploit-kit staging pattern.
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` `36d0c64d490ab92203c6a310d862fffee8547108c1cb24e7835350c0946c76c3`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	611 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).

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