Understanding Shellcode Example

Question

in the silk code tutorial, I saw the following example:

 main(){

    exit(0);

 }

The idea was to create exit () - syscall. So they build:

  Section .text

      global _start

 _start:
      mov ebx, 0
      mov eax, 1
      int 0x80

I understand it. 0 is the exit () argument that we save in ebx, 1 is the syscall exit number, and from 0x80 we change the CPU to kernel mode and syscall is executed.

After that, they allow you to create operation codes that:

    bb 00 00 00 00
    b8 01 00 00 00
    cd 80

Then they translate this into a C language that looks like this:

 char example[] = "\xbb\x00\x00\x00\x00"
                  "\xb8\x01\x00\x00\x00"
                  "\xcd\x80"

  int main(){

  int *pointer; 
  pointer = (int *)&pointer+2;
  (*pointer) = (int)example;
  }

So, I understand that they take opcodes in the char array, but I don’t understand what they did in the main () method. The first line is fine. But what do they want to express on the 2nd and 3rd lines?

Yours faithfully,

Answer 1

, , . , , .

, , , . .

---

(.. , , , "" ): , "" ; , , .