Buffer Overflows and Shellcode
Explore the mechanics of buffer overflow vulnerabilities and how they can be exploited to inject and execute malicious shellcode.
Intro: Buffer Overflows
Welcome to a critical topic in low-level security: Buffer Overflows. These are a type of software vulnerability that can allow attackers to gain control over a program.
Essentially, a buffer overflow occurs when a program tries to write more data into a fixed-size memory buffer than it was designed to hold. This excess data 'overflows' into adjacent memory regions.
What's a Buffer?
In programming, especially in languages like C or assembly, a buffer is simply a block of memory reserved for storing data. Think of it like a container with a specific capacity.
- Buffers are often used for temporary storage, like holding user input or network data.
- They can be declared as arrays of characters (strings) or other data types.
- For example,
char username[32];declares a buffer that can hold up to 31 characters plus a null terminator.
All lessons in this course
- Cache Coherency and Performance
- Hand-Optimizing Critical Sections
- Buffer Overflows and Shellcode
- Branch Prediction and Speculative Execution