Memory leak in ProFTPd 1.2.0rc2 allows remote attackers to cause a denial of service via a series of USER commands, and possibly SIZE commands if the server has been improperly installed.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2001-0136
http://www.securityfocus.com/archive/1/152206
http://www.linux-mandrake.com/en/security/2001/MDKSA-2001-021.php3
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000380
http://archives.neohapsis.com/archives/bugtraq/2001-02/0267.html
http://archives.neohapsis.com/archives/bugtraq/2001-01/0132.html
http://archives.neohapsis.com/archives/bugtraq/2001-01/0122.html