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SMTP being hijacked - trying to block sender

steagle
Looks like over the weekend we got hijacked and now I have spammers from Italy using our SMTP relay to send thousands of emails. I have added their domains to the sender blacklist filter and the expression filter, but the emails continue to pour through. Obviously, I'm not using the right tool to stop them. I've got a list of the domains they're using - does anyone know how I can block these guys? Thanks!

edit: Also realized this could be a malware intrusion on one of our workstations - we are currently scanning all machines with Malwarebytes to see if we can find the culprit. Just in case this is not the issue and we indeed have been hijacked, any tips for dealing with this would be highly appreciated. 
____

ASG220
Firmware 7.501
Pattern Version 22662


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  • 0
    Are all of these emails coming from the same source IP or at least netblock?

    What mitigation techniques do you have enabled in the SMTP proxy currently?

    I noticed that the IP address in the example spam mail header listed above is in the xbl.spamhaus.org and cbl.abuseat.org DNSBL lists.  You may want to consider adding these as extra RBL zones (I personally prefer to use the zen database for spamhaus, as it is inclusive of all of their databases.).
    __________________
    ACE v8/SCA v9.3

    ...still have a v5 install disk in a box somewhere.

    http://xkcd.com
    http://www.tedgoff.com/mb
    http://www.projectcartoon.com/cartoon/1
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  • 0
    Are all of these emails coming from the same source IP or at least netblock?

    What mitigation techniques do you have enabled in the SMTP proxy currently?

    I noticed that the IP address in the example spam mail header listed above is in the xbl.spamhaus.org and cbl.abuseat.org DNSBL lists.  You may want to consider adding these as extra RBL zones (I personally prefer to use the zen database for spamhaus, as it is inclusive of all of their databases.).
    __________________
    ACE v8/SCA v9.3

    ...still have a v5 install disk in a box somewhere.

    http://xkcd.com
    http://www.tedgoff.com/mb
    http://www.projectcartoon.com/cartoon/1
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