[Assp-test] ASSP involved in relaying exploit for Sendmail

[JP v. M. <jp...@ds...>]

Hi again,

Sendmail is relaying mail because it thinks it's coming from its own IP.
This happens when the proxy is in between.

Here are 3 telnet SMTP-sessions.
The 2nd one is able to do an open relay.
They are all talking to the same sendmail.




Sendmail listens on: 82.150.128.198:225
ASSP listens on: 82.150.128.198:25


Foreign domain connecting to SENDMAIL
[root@fc mail]# telnet 82.150.128.198 225
Trying 82.150.128.198...
Connected to 82.150.128.198.
Escape character is '^]'.
220 smtp.dsdeurne.nl ESMTP Sendmail 8.13.8/8.13.8; Mon, 25 Feb 2008 14:47:25
+0100
helo hetemail.com
250 smtp.dsdeurne.nl Hello cust-03-55bf00f1.adsl.scarlet.nl [85.191.0.241],
pleased to meet you
mail from: <no...@sm...>
250 2.1.0 <no...@sm...>... Sender ok
rcpt to: <mirmana.com!jp...@sm...>
550 5.7.1 <mirmana.com!jp...@sm...>... Relaying denied
quit
221 2.0.0 smtp.dsdeurne.nl closing connection
Connection closed by foreign host.


Foreign domain connecting to ASSP                       OPEN RELAY!!!!!!!
[root@fc mail]# telnet 82.150.128.198 25
Trying 82.150.128.198...
Connected to 82.150.128.198.
Escape character is '^]'.
helo hetemail.com
mail from: <no...@sm...>
rcpt to: <mirmana.com!jp...@sm...>
220 smtp.dsdeurne.nl ESMTP Sendmail 8.13.8/8.13.8; Mon, 25 Feb 2008 14:48:30
+0100
250 smtp.dsdeurne.nl Hello smtp.dsdeurne.nl [82.150.128.198], pleased to
meet you
250 2.1.0 <no...@sm...>... Sender ok
250 2.1.5 <mirmana.com!jp...@sm...>... Recipient ok

Foreign domain connecting to ASSP
[root@fc mail]# telnet 82.150.128.198 25
Trying 82.150.128.198...
Connected to 82.150.128.198.
Escape character is '^]'.
220 smtp.dsdeurne.nl ESMTP Sendmail 8.13.8/8.13.8; Mon, 25 Feb 2008 15:13:08
+0100
helo hetemail.com
250 smtp.dsdeurne.nl Hello smtp.dsdeurne.nl [82.150.128.198], pleased to
meet you
mail from: <no...@sm...>
250 2.1.0 <no...@sm...>... Sender ok
rcpt to: <jp...@mi...>
530 Relaying not allowed