How can you protect your program from buffer underrun attacks?

2 What causes buffer underrun attacks?

Buffer underrun attacks happen when a program does not check the size of the buffer before reading from it. This can lead to reading data from outside the buffer's boundaries, which might contain garbage values, sensitive information, or malicious code. For instance, if you have a buffer of 10 bytes and you try to read 12 bytes from it, you might end up reading 2 bytes from another memory location that you do not own or control.

3 How to detect buffer underrun attacks?

Buffer underrun attacks can be hard to detect because they do not always cause visible errors or crashes. However, they can affect your program's functionality, performance, and security in subtle ways. For example, they can corrupt your data, leak your secrets, or execute arbitrary code. To detect buffer underrun attacks, you need to use debugging tools that can monitor your memory usage and access patterns. Some examples of such tools are Valgrind, AddressSanitizer, and GDB.

4 How to prevent buffer underrun attacks?

The best way to prevent buffer underrun attacks is to avoid using unsafe functions that do not check the buffer size before reading from it. For example, in C and C++, you should avoid using functions like gets, scanf, and strcpy, and use safer alternatives like fgets, sscanf, and strncpy instead. You should also use static analysis tools that can warn you about potential buffer underrun vulnerabilities in your code. Some examples of such tools are Clang, GCC, and Visual Studio.

5 How to handle buffer underrun errors?

Sometimes, you might encounter buffer underrun errors that are not caused by malicious attacks, but by legitimate conditions or situations. For example, you might have a buffer that is too small for the data you want to read, or you might have a network connection that is too slow or unreliable. In these cases, you need to handle the buffer underrun errors gracefully and recover from them. You can do this by using error checking and exception handling mechanisms, such as errno, assert, and try-catch-finally.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?