deobfuscating-javascript-malware

# Deobfuscating JavaScript Malware ## When to Use - Investigating a phishing page with obfuscated JavaScript that performs credential harvesting or redirect - Analyzing a web skimmer (Magecart-style) injected into an e-commerce site - Deobfuscating a JavaScript dropper that downloads and executes second-stage malware - Examining malicious email attachments containing HTML files with embedded obfuscated scripts - Analyzing browser exploit kits that use heavy JavaScript obfuscation to hide exploit delivery **Do not use** for obfuscated JavaScript that is merely minified production code; use a standard beautifier instead. ## Prerequisites - Node.js 18+ installed for executing and debugging JavaScript in a controlled environment - Python 3.8+ with `jsbeautifier` library for code formatting - Browser developer tools (Chrome DevTools) for controlled execution in an isolated browser - CyberChef (https://gchq.github.io/CyberChef/) for encoding/decoding operations - de4js or JStillery for automated JavaScript deobfuscation - Isolated analysis VM with no access to production systems or sensitive data ## Workflow ### Step 1: Safely Extract and Examine the Obfuscated Script Isolate the malicious JavaScript without executing it: ```bash # Extract JavaScript from HTML file python3 << 'PYEOF' from html.parser import HTMLParser class ScriptExtractor(HTMLParser): def __init__(self): super().__init__() self.in_script = False self.scripts = [] self....