Stop Spamming in the server

Stop Spamming in the server

Stop Spamming

The file '/etc/antivirus.exim' is a central filter for the exim mail server that let us setup powerful filters to help stop spam mails from coming in/going out to/from our server.


1. First of all we need to create a special log file for these filters

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


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

vi /etc/antivirus.exim


3. Simply copy the following lines of code to the /etc/antivirus.exim file

[For better understanding let me classify them as blocks]


######################################################

# START
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
#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
######################################################



4. The log file will have the logging format as follows
cat /var/log/filter.log

2007-03-27 12:05:13 1Fds7S-0002Sa-MV from smooth595@gmail.com This e-mail address is being protected from spambots. You need JavaScript enabled to view it contained spam keywords
2007-03-27 14:18:47 1FduCn-0006GV-1r from dayton.nowellu7xn@gmail.com This e-mail address is being protected from spambots. You need JavaScript enabled to view it contained spam keywords
2007-03-27 15:44:35 1FZDLn-0005Mo-5z from nobody@ocean.wavepointmedia.com This e-mail address is being protected from spambots. You need JavaScript enabled to view it is fraud
2007-03-27 16:37:40 1FZEB9-0002KQ-VP from nobody@ocean.wavepointmedia.com This e-mail address is being protected from spambots. You need JavaScript enabled to view it is phishing



5. All the fields are self explanatory and thus we can add new rules according to our need


6. :)