What’s a buffer overflow?
Buffer overflows are a type of vulnerability where the attacker gives more data to a buffer than it can handle. As a result, the program overwrites adjacent memory locations with the exceeding data. Usually, the program will crash. However, a skilled hacker can take control of the program as it crashes and achieve incredible things, like access to a shell. Nowadays, there are some countermeasures in place. They make it much harder but not impossible. Especially if using languages like C or C++, that lets developers manage the memory.
There are two types of buffer overflows: stack-based and heap-based. In this post, we will talk about the first type.