#Buffer overflow tutorial code#

Registers are CPU variables that sore single records, there are a fixed number of registers that are used for different purposes and they all have a specific location in the CPU.

#Buffer overflow tutorial code#

The ESP CPU register points to the lowest part of the stack and anything below it is free memory that can be overwritten, which is why it is often exploited by injecting malicious code into it.

The stack always grows downwards towards lower values as new information is added to it. The stack is a section of memory that stores temporary data, that is executed when a function is called. This will come useful when redirecting the application execution as the JMP ESP instruction address will have to be stored in reverse in the exploit. 0x0BADF00D will be stored as “0DF0AD0B”.0x032CFBE8 will be stored as “E8FB2C03”.In little endian, the bytes are stored in reverse order. Whenever an executable is run, its code is loaded into memory so that it can perform all the tasks that is has been programmed to do, because all of the instructions are loaded onto the program’s memory, this can be changed thus making the application perform unintended actions.Īll variables in memory are stored using either little endian (for intel x86 processors) or big endian (for PowerPC) format.

Normally, a process is allocated a certain amount of memory which contains all of the necessary information it requires to run, such as the code itself and any DLLs, which isn’t shared with other processes.