What is Virtual Protect?

Question

C++ / C#

Hello, I googled a lot on this topic, but I can’t understand what the VirtualProtect and VirtualProtectEx functions do in general? As I understand virtualProtect changes something... But I don't understand what. If it’s not difficult, you can explain in human language what it is and what it is eaten with.

Answer 1

The OS can block the ability for an application to read, write, execute certain ranges of virtual memory. For example, the code *((char*)GetProcAddress(hkernel32, "GetProcAddress")) = 0 will throw an exception by default. But if you give the memory region write permissions, then the first byte of the function in this process will be successfully overwritten.