Barracuda Spam Firewall <= 3.1.10 acts as open relay for whitelisted senders.
Description (www.barracudanetworks.com):
The Barracuda Spam Firewall is an integrated hardware and software
solution for complete protection of your e-mail server. It provides a
powerful, easy to use, and affordable solution to eliminate spam and
viruses from your organization.
Synopsis:
Under normal circumstances, the Barracuda Spam Firewall only relays
traffic for domains it is configured for. If a sender's domain or the
Barracuda's own domain is whitelisted, however, all rules are bypassed
and the Barracuda becomes an open relay for all e-mail sent from the
whitelisted domain. This is unacceptable behavior, and whitelisted
senders should only be able to send e-mail to domains for which the
Barracuda is configured to relay.
Effected Versions:
<= Firmware 3.1.10 Open Relay for Whitelisted Domains
>= Firmware 3.1.11 Fixed (Firmware 3.1.12 Released 02/09/2005)
Notes:
Although I found this bug last week while evaluating the Barracuda Spam
Firewall Model 200 (Firmware 3.1.10), a quick search of Barracuda
Networks' forums revealed other customers had complained about the same
problem.
http://forum.barracudanetworks.com/bb/viewtopic.php?t=1545
http://forum.barracudanetworks.com/bb/viewtopic.php?t=1627
http://forum.barracudanetworks.com/bb/viewtopic.php?t=1535
Vendor Response via E-mail (02/08/2005):
The initial vendor response was misleading and inferred that the
Barracuda will only become an open relay if you whitelist your own
domain.
Under the Block/Accept -> Sender Domain Block/Accept tab, if you do not
whitelist your own domains, you do not have to worry about the relaying
issue. Open relaying means people telnet to the Barracuda on port 25,
use "mail from: anybody@xxxxxxxxxx" and then "rcpt to" somewhere else on
the Internet. Your Barracuda is rejecting these activities and returns
"Recipient address rejected: No such domain at this location" when the
"rcpt to" domain is not one of the "Allowed Recipient Domains."
Your test below was successful because it is the same way that mails are
sent into your network.
Vendor Response via E-mail (02/09/2005):
The second vendor response verified my findings and confirmed a fix
would be available.
Basically anything in that causes the the email to be white listed will
bypass the scanning engine.
This is going to cause the barracuda to be a open relay, this issue is
fixed on the next release of the firmware.
The new firmware should be released by next week.
Release Notes (3.1.11):
Fix: Whitelisted senders no longer have the potential to use the
Barracuda as a relay. Messages are rejected before acceptance instead
of afterwards if destined for a domain not listed on the system.
/Sean/