PDF malware analysis — malicious · 815b11f077bd3cf7

MALICIOUS

PDF

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

MD5: c2c24104adbcf0afc0802fa595288087 SHA-1: ac2e7d42c4289713569454a60b312d79411a73dd SHA-256: 815b11f077bd3cf72e671c1095b927f8f01f3677490dad8249d8ced616ff7ea1

94 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded JavaScript within its metadata, flagged by high-severity heuristics like 'PDF_METADATA_EVAL_STAGER'. This JavaScript, likely obfuscated using String.fromCharCode, is designed to execute arbitrary code. The primary function appears to be a stager, intended to download and execute a second-stage payload. The ML classifier strongly indicates maliciousness.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 4

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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0001_000.js` `6ef3f41068a6947225b7edbdf917dbc572d53afc107dc3814cce58da719b4fea`	pdf-javascript-stream	PDF /JS object 1 at offset 0x628E	528 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.