Final answer:
A stack buffer overflow happens when more data is written to a buffer on the stack than it was intended to hold, leading to possible arbitrary code execution. Attackers might exploit this by overwriting adjacent memory areas and redirecting program execution. Preventative measures include automatic bounds checking and memory protection mechanisms.
Step-by-step explanation:
A stack buffer overflow occurs when the targeted buffer is located on the stack, usually as a local variable in a function's stack frame. This type of security vulnerability happens when a program writes more data to a buffer than it is designed to hold. Due to insufficient bounds checking, this can lead to adjacent memory spaces being overwritten, which may contain control information for the execution of the program, such as return addresses.
Attackers may exploit stack buffer overflows by providing carefully crafted input that, when processed by the program, causes it to execute arbitrary code. This is often done by injecting malicious code or by manipulating the stack control mechanisms, such as the return pointer, to redirect the program execution flow to the attacker's code. Preventative measures include using modern languages that perform automatic bounds checking, employing stack canaries, and utilizing memory protection mechanisms provided by the operating system.
Understanding and preventing buffer overflows are crucial in building secure software. Developers and IT security professionals are often tasked with the responsibility of ensuring that software is free from such vulnerabilities by adopting secure coding standards and practices.