Filter rules for exim server antivirus.exim file

Hello,

First off we need to create a special log file for these filters do this:

touch /var/log/filter.log
chmod 0644 /var/log/filter.log

Now open up the configuration file
vi /etc/antivirus.exim

It should have a whole whack of comments at the top.

Here’s the webhostgear.com antivirus.exim configuration. Simple add this to your existing file, save the changes and they take effect instantly.



### CUSTOM WEBHOSTGEAR.COM FILTERS by Steven Leggett info@webhostgear.com
######################################################

# START
# Filters all incoming an outgoing mail


logfile /var/log/filter.log 0644
## Common Spam
if

# Header Spam
$header_subject: contains "Pharmaceutical"
or $header_subject: contains "Viagra"
or $header_subject: contains "Cialis"
or $header_subject: is "The Ultimate Online Pharmaceutical"
or $header_subject: contains "***SPAM***"
or $header_subject: contains "[SPAM]"


# Body Spam
or $message_body: contains "Cialis"
or $message_body: contains "Viagra"
or $message_body: contains "Leavitra"
or $message_body: contains "St0ck"
or $message_body: contains "Viaagrra"
or $message_body: contains "Cia1iis"
or $message_body: contains "URGENT BUSINESS PROPOSAL"
or $message_body matches "angka[^s]+[net|com|org|biz|info|us|name]+?"
or $message_body matches "v(i|1)agra|vag(i|1)n(a|4)|pen( i|1)s|asu|seks|l(o|0)l(i|1)ta|dewacolok"

then
# Log Message - SENDS RESPONSE BACK TO SENDER
# SUGGESTED TO LEAVE OFF to prevent fail loops
# and more work for the mail system
#fail text "Message has been rejected because it hasn
# triggered our central filter."
logwrite "$tod_log $message_id from $sender_address contained spam keywords"

seen finish
endif


# END
# Filters all incoming an outgoing mail


# START
# All outgoing mail on the server only - what is sent out

#Check forwarders so it doesn't get blocked
#Forwarders still work =)

## FINANCIAL FAKE SENDERS
## Log all outgoing mail from server that matches rules
logfile /var/log/filter.log 0644
if (
$received_protocol is "local" or
$received_protocol is "esmtpa"
) and (
$header_from contains "@citibank.com" or
$header_from contains "@bankofamerica.com" or
$header_from contains "@wamu.com" or
$header_from contains "@ebay.com" or
$header_from contains "@chase.com" or
$header_from contains "@paypal.com" or
$header_from contains "@wellsfargo.com" or
$header_from contains "@bankunited.com" or
$header_from contains "@bankerstrust.com" or
$header_from contains "@bankfirst.com" or
$header_from contains "@capitalone.com" or
$header_from contains "@citizensbank.com" or
$header_from contains "@jpmorgan.com" or
$header_from contains "@wachovia.com" or
$header_from contains "@bankone.com" or
$header_from contains "@suntrust.com" or
$header_from contains "@amazon.com" or
$header_from contains "@banksecurity.com" or
$header_from contains "@visa.com" or
$header_from contains "@mastercard.com" or
$header_from contains "@mbna.com"
)
then
logwrite "$tod_log $message_id from $sender_address is fraud"
seen finish
endif

## OTHER FAKE SENDERS SPAM
## Enable this to prevent users using @domain from addresses
## Not recommended since users do use from addresses not on the server
## Log all outgoing mail from server that matches rules
logfile /var/log/filter.log 0644
if (
$received_protocol is "local" or
$received_protocol is "esmtpa"
) and (
$header_from contains "@hotmail.com" or
$header_from contains "@yahoo.com" or
$header_from contains "@aol.com"


)
then
logwrite "$tod_log $message_id from $sender_address is forged fake"
seen finish
endif



## KNOWN FAKE PHISHING
### Log all outgoing mail from server that matches rules
logfile /var/log/filter.log 0644
if (
$received_protocol is "local" or
$received_protocol is "esmtpa"
) and (
#Paypal
$message_body: contains "Dear valued PayPal member" or
$message_body: contains "Dear valued PayPal customer" or
$message_body: contains "Dear Paypal" or
$message_body: contains "The PayPal Team" or
$message_body: contains "Dear Paypal Customer" or
$message_body: contains "Paypal Account Review Department" or


#Ebay
$message_body: contains "Dear eBay member" or
$message_body: contains "Dear eBay User" or
$message_body: contains "The eBay team" or
$message_body: contains "Dear eBay Community Member" or


#Banks
$message_body: contains "Dear Charter One Customer" or
$message_body: contains "Dear wamu.com customer" or
$message_body: contains "Dear valued Citizens Bank member" or
$message_body: contains "Dear Visa" or
$message_body: contains "Dear Citibank" or
$message_body: contains "Citibank Email" or
$message_body: contains "Dear customer of Chase Bank" or
$message_body: contains "Dear Bank of America customer" or




#ISPs
$message_body: contains "Dear AOL Member" or
$message_body: contains "Dear AOL Customer"


)
then
logwrite "$tod_log $message_id from $sender_address is phishing"
seen finish
endif

# END
# All outgoing mail on the server only - what is sent out



The log file will have the logging format like this:
/var/log/filter.log

2006-05-10 12:05:13 1Fds7S-0002Sa-MV from smooth595@gmail.com contained spam keywords
2006-05-10 14:18:47 1FduCn-0006GV-1r from dayton.nowellu7xn@gmail.com contained spam keywords
2006-04-27 15:44:35 1FZDLn-0005Mo-5z from nobody@ocean.wavepointmedia.com is fraud
2006-04-27 16:37:40 1FZEB9-0002KQ-VP from nobody@ocean.wavepointmedia.com is phishing


Date and time, the Exim message ID, the sender and the section of the filter, like phishing, fraud or spam. You can check the mail message by grepping the exim_mainlog for it like this

grep 1FZEB9-0002KQ-VP /var/log/exim_mainlog

If you haven’t already you should enable a higher level of logging in your mail server which will be in our next tutorial.

Enjoy