Impossible Disassembly Anti-Disassembly

Impossible disassembly is an anti-disassembling technique that involves inserting data bytes after a conditional jump instruction in order to prevent the real instruction that follows from being disassembled. This technique takes advantage of a basic assumption in disassembly, which states that one byte is only interpreted in the context of one instruction. By inserting a byte that is the opcode …

Obscuring Control Flow Anti-Disassembly

Obscuring control flow is an anti-disassembling technique that involves using methods of flow control that are difficult or impossible for disassemblers and debuggers to follow. This can make it more difficult for analysts to understand the program's behavior and can also make it more difficult for other tools, such as debuggers, to accurately interpret the program.

One example of this …

Disassembly Desynchronization Anti-Disassembly

Disassembly desynchronization is a technique that is used to prevent disassemblers from accurately reconstructing the original instructions of a program. It involves the creative use of instructions and data in a way that breaks the normal, predictable sequence of instructions in a program. This can cause disassemblers to become "desynchronized" and generate incorrect disassembly output.

For example, suppose a program …

Jump With Same Target Anti-Disassembly

Jump with the same target is an anti-disassembling technique that involves using back-to-back conditional jump instructions that both point to the same target. This can make it difficult for a disassembler to accurately reconstruct the original instructions of the program, as the disassembler will not be able to determine the intended behavior of the program without actually executing it.

For …

Thwarting Stack-Frame Analysis Anti-Disassembly

Thwarting Stack-Frame Analysis is a technique used by malware to make it more difficult for security analysts to reverse engineer and analyze the code. A stack frame is a collection of data associated with a function, including local variables, arguments passed to the function, and the return address. Disassemblers can use information from the stack frame to understand a function's …

Opcode Obfuscation Anti-Disassembly

Opcode obfuscation is an anti-disassembling technique that involves modifying the opcodes of a program's machine language instructions in order to make it more difficult for a disassembler to accurately reconstruct the original instructions. This can be done in a variety of ways, such as by using equivalent but different opcodes for the same operation, by adding additional instructions or data …