Reverse Engineering Notes - Pattern Recognition

 

This is a list of common function patterns that you might encounter when examining assembly code:

1. Prologue and epilogue: Many functions in assembly language will start with a prologue and end with an epilogue that sets up and tears down the function's stack frame. The prologue usually saves the previous frame pointer and the return address, while the epilogue restores them and deallocates any local variables that were pushed onto the stack.

2. Argument handling: In many cases, function arguments are passed on the stack or in registers. You can often identify the argument handling code by looking for instructions that access memory locations where the arguments are stored.

3. Function call: When one function calls another, it will often pass arguments in registers or on the stack, then jump to the called function's address. You can identify a function call by looking for instructions that push arguments onto the stack, load the address of the called function, and perform a jump or call operation.

4. Looping constructs: Functions that include loops will often include conditional jump instructions that test a counter or flag value and jump back to the start of the loop if the condition is met. You can identify looping constructs by looking for instructions that include jump or conditional jump operations.

5. Memory operations: Functions that manipulate memory will often include instructions that load or store values from or to specific memory addresses. You can identify memory operations by looking for instructions that include load or store operations, as well as by looking at the memory addresses being accessed.

6. Arithmetic and logical operations: Functions that perform arithmetic or logical operations on data will often include instructions that add, subtract, multiply, divide, or perform logical operations like AND, OR, and XOR. You can identify arithmetic and logical operations by looking for instructions that include these operations, as well as by looking at the registers or memory locations being used as operands.

7. Control flow operations: Functions that perform conditional branching or other control flow operations will often include instructions that compare values, test flags, or perform other operations to determine which code path to take. You can identify control flow operations by looking for instructions that include conditional jumps or other control flow operations.

SIDE NOTE::These are just a few examples of the kinds of patterns you might encounter when examining assembly code. The specific patterns you'll encounter will depend on the programming language, platform, and compiler used to generate the code.