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Branch Encryption
a day ago
- Branch encryption prevents attackers from knowing or inferring program states before they are reached.
- It protects constant data (e.g., passwords) used in comparisons by replacing them with hashed values.
- Encrypted code blocks inside conditional statements can only be decrypted with the correct input key.
- The technique combines hashing for comparison and encryption for conditional code execution.
- An example with JavaScript shows how hashing and XOR encryption can hide a password and secret message.
- Branch encryption is useful for protecting comparison values and associated code or data.
Javascript obfuscation tricks
a day ago
- Functions can read themselves via comments, allowing arbitrary string data to be embedded and used; deobfuscators that remove comments will break the code.
- Stack trace line and column numbers can be used as encryption keys; reformatting or removing functions changes these numbers, causing decryption to fail.
- Browser crashes can be triggered by async fork bombs (e.g., async function calling itself twice) that hide the crash location in devtools.
- Variable names can be extracted as strings through object key iteration, enabling data storage in identifiers and enforcing name integrity with eval.
- To thwart LLM-based deobfuscation, embed threatening Base64 instructions (with noise) that cause models to refuse, or overload the context window by making every code segment essential.
Overview of JavaScript Virtualization Obfuscation
a day ago
- No code protection is unbreakable because computers must see instructions to execute them, so the goal is to abstract program execution.
- Virtualization obfuscation involves creating a fantasy CPU, compiling input code to its instruction set, and running it in an interpreter, similar to the Java Virtual Machine.
- Web protections (JavaScript) are generally easier to crack than binary protections, as binary security has a more established scene.
- A basic example shows a program as an array of instruction IDs and operands, with a loop that interprets instructions like push and add.
- Monitoring program memory can break such virtualized code, just like executable programs.
Try-Catch Control Flow Obfuscation
a day ago
- JavaScript exception handling can be exploited to create non-linear code flow that confuses analysis.
- Attackers can force errors in try blocks to jump to catch blocks, hiding the actual intended functionality.
- The catch block executes real logic, often with conditional checks based on state set in the try block.
- Chaining multiple try-catch blocks creates complex execution paths that only reach specific code through specific error chains.
- It is important to avoid making it obvious that the function always throws an error, as that makes the pattern easier to detect.

obfuscation

Branch Encryption

Javascript obfuscation tricks

Overview of JavaScript Virtualization Obfuscation

Try-Catch Control Flow Obfuscation