Home > Linux, security > Enabling stack randomization in linux

Enabling stack randomization in linux

 

One way to make the process of exploiting buffer overflow vulnerabilities harder is to enable stack randomization feature.

In case of disabling stack randomization features, it’s so easy for the hacker to guess the address of the first instruction  in the shell code based on the offset from the beginning of the stack, so that to make the life  harder to the hacker (not good ones) we ‘ll enable this feature as shown below:

sysctl -w kernel.randomize_va_space=2

So, if we write a small c program to return with the address of the top of the stack,

#include <stdio.h>

unsigned long topOfStack(void){
__asm__(“movl %esp, %eax”);
}

int main(void){
printf(“%x\n”, topOfStack());
return 0;
}

and then run it more, the result ‘ll be as shown:

865198e0
a806d0b0
5fffb230

and so no.

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Categories: Linux, security Tags: , , , ,
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