How to use AI to extract IOCs from malware in JavaScript

I downloaded a random sample in JavaScript on MalwareBazaar : SHA256 51e81f26e93788c213139654365a5a5723a65b6c08662c68b38b1825338b8651

In the digital age, JavaScript malware has become increasingly prevalent, posing a significant threat to internet users and organizations worldwide. Nowadays, virtually all JavaScript malware features some level of decryption or decoding functionality, complicating the task of cybersecurity experts who must identify, analyze, and mitigate these threats. In this article, we will explore the fundamentals of JavaScript malware, examine the basic decryption and decoding techniques employed by attackers, and discuss strategies for combating these threats effectively.

JavaScript malware refers to malicious code embedded within JavaScript files, often used to exploit vulnerabilities in web browsers, web applications, or the underlying operating system. By leveraging the power and ubiquity of JavaScript, cybercriminals can target a vast array of devices, making it an attractive option for launching cyber-attacks.

Decryption and Decoding Techniques: As cybercriminals grow increasingly sophisticated, they have turned to encryption and encoding techniques to evade detection and hinder analysis. Here are some common methods employed in JavaScript malware:

1. Obfuscation: Attackers typically use obfuscation to make their malicious code harder to read and understand. This technique can involve renaming variables and functions, using complex control structures, or employing encoding schemes.
2. Base64 Encoding: Base64 is a widely-used encoding method that can disguise malicious payloads by representing binary data in an ASCII string format. JavaScript's malware typically employs this technique to conceal its true intentions.
3. XOR Encryption: XOR encryption is a simple but effective method for encrypting data by applying a bitwise exclusive OR operation with a predefined key. In JavaScript malware, this technique can be used to encrypt malicious payloads, which are then decrypted at runtime.
4. Custom Encoding Schemes: Some attackers develop their own encoding schemes to further complicate analysis and avoid detection by signature-based security solutions.

To capture attention, let’s revamp the sentence: “My initial strategy is to meticulously sanitize the script by eliminating any distracting comments and noise introduced by the attacker, paving the way for a clearer analysis.

With the cleaning process complete, we now have a significantly refined code, providing us with an excellent foundation to strategize and determine our next course of action.

After talking with AI 30 minutes, I was able to decrypt the original code without issues and create the script to do that.

JsDecryptAI/script.js at main · andreisss/JsDecryptAI

Part of the script :

Countermeasures for JavaScript Malware: To defend against JavaScript malware and its decryption or decoding techniques, consider adopting the following strategies:

1. Keep Software Up-to-Date: Regularly update your web browsers, operating systems, and security software to protect against known vulnerabilities exploited by JavaScript malware.
2. Use Strong Security Solutions: Employ advanced security solutions capable of detecting and blocking obfuscated, encrypted, or encoded JavaScript malware.
3. Disable Unnecessary Features: Consider disabling JavaScript in your web browser when not needed, or use browser plugins that selectively enable JavaScript for trusted websites.
4. Educate Users: Train users to recognize social engineering attacks, such as phishing emails, which may deliver JavaScript malware payloads.

Conclusion: As JavaScript malware continues to evolve, incorporating decryption and decoding techniques to evade detection and analysis, it’s crucial to stay informed about the latest threats and adopt effective countermeasures. By understanding the underlying techniques and implementing robust security strategies, you can protect your digital assets and maintain a safe online environment.