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Re: [FW-1] Secure SMTP server used for spam relay



I was thinking what could be causing this and I was wondering if the problem
is that I did the automatic STATIC NAT and Auto ARP.  Would it be better if
I did this manually or does the Auto stuff in Checkpoint work pretty well on
Win2K?

Trent Libby

-----Original Message-----
From: Trent Libby [mailto:[email protected]]
Sent: Monday, August 26, 2002 5:28 PM
To: [email protected]
Subject: Re: [FW-1] Secure SMTP server used for spam relay

Sounds like you have a open relay on your email server.  I had one of those
at a customer site and to stop it I had to make it where only authenticated
users could send out of their server.

Trent Libby

-----Original Message-----
From: Francis Lachance
To: [email protected]
Sent: 8/26/02 1:05 PM
Subject: [FW-1] Secure SMTP server used for spam relay

Hi,

It seems our CheckPoint FW-1 was used to relay spam mail, here are  the
details.

CheckPoint FW-1 4.1 SP6 on NT 4

We have no DMZ so our mail server is on the internal segment and have
only
two valid address available to us (one for the fw external interface and
one
for the router).
We have a little mail server inside used by only a few users.The FW-1
SMTP
Security Server is enabled and I have the following rules for SMTP:
>From Any to firewall smtp(incoming) accept
>From mailserver to Any smtp(outgoing) accept
The incoming resource states that the sender can be anybody (*) but the
recipients has to be in our domain (*@ourdomain.com)
The outgoing resource states that the sender has to be in our domain
(*@ourdomain.com) and the recipients can be anybody.

The security group found out that spammers were using the firewall to
relay
mail by changing the sender to be [email protected].

Since we only have a few users I changed the incoming resource to state
that
the recipients can only be specific users
({user1,user2,user3}@ourdomain.com).
Same thing for the outgoing resource the sender has to match a valid
user to
send.

After these changes I feeled we were ok but the security group stated
that
we were still vulnerable to spammers and therefore had to disable our
smtp
service. What they do is they run the chkspam perl script
(http://vancouver-webpages.com/pub/chkspam) against our firewall
external
interface and get the following results:
220 CheckPoint Firewall-1 secure SMTP server
requires HELO: NO
allows VRFY username verification: YES
allows EXPN forwarding expansion: NO
allows bogus From: header: YES
allows simple mail relaying: YES
may allow UUCP mail relaying: NO
allows other mail relaying: NO
can mail to postmaster: NO
can mail to webmaster: NO
can mail to abuse (RFC 2142): NO

That test looks like it was meant to test Sendmail server is there
anyway
that a CheckPoint secure SMTP server can pass that kind of test ?
Anybody
had that kind of trouble with the secure SMTP server ?

Thanks
Francis

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=================================================
To set vacation, Out Of Office, or away messages,
send an email to [email protected]
in the BODY of the email add:
set fw-1-mailinglist nomail
=================================================
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please see the instructions at
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