Malware is used for a malicious purpose. It can be in your software or hardware. Email and pirated software is the most powerful way to spread malware. Malware inserted in a system without user notification.
Wikipedia defines Malware as:
Malware is software designed to infiltrate or damage a computer system without the owner’s informed consent. It is a portmanteau of the words “malicious” and “software”. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code.
It will be a nice idea to block malware spreading URLs and website. Setting up a malware blacklist in Postfix MTA is quite easy. The Malware Block List is a free, automated and user contributed system for checking URLs for the presence of Viruses, Trojans, Worms, or any other software considered Malware.
Create a blacklist
First you need to create a blacklist, type the following command:
# wget -O - 'https://lists.malwarepatrol.net/cgi/getfile?receipt=f1391767429&product=8&list=postfix' > /etc/postfix/mbl-body-deny
Where receipt= should be followed by your personal Malwarepatrol id once registered. Do not use f1391767429. This is for demo purpose only.
Configure Postfix
Open postfix main.cf config file, run:
# vi /etc/postfix/main.cf
Setup postfix body_check directive as follows:
body_checks = regexp:/etc/postfix/mbl-body-deny
Save and close the file.
Restart Postfix
Now just restart the postfix daemon:
# postmap /etc/postfix/mbl-body-deny
# /etc/init.d/postfix restart
Automate procedure
You need to setup a cron job to automate entire procedure. Create a shell script as follows:
#!/bin/bash # Script to update malware urls # Author: Vivek Gite <www.cyberciti.biz> under GPL v2.x+ # --------------- # Set https://malwarepatrol.net/ ID here (it is free) myid="" [[ ! -z "$myid" ]] && echo "Using $myid..." || { echo "Error: Please correct set \"$myid\"."; exit 1; } /usr/bin/wget -O - "https://lists.malwarepatrol.net/cgi/getfile?receipt=${myid}&product=8&list=postfix" > /etc/postfix/mbl-body-deny /usr/sbin/postmap /etc/postfix/mbl-body-deny /etc/init.d/postfix reload |
Add cronjob as follows:
40 23 * * * /etc/admin/scripts/fetch.postfixmalware.sh >/dev/null 2>&1
You may wan to combine this feature with mime attachments blocking and anti spam blacklist for the best result.
16 comment
I’m giving it a try, even though the current list shows to have some duplicates.
Oh and AFAIK “postfix reload” will do fine too (instead of restarting)!
BOK,
Yes, reload is fine too, I’ve used reload in script. Just checked my log and there are 4 dupes. But it works like a charm on our anti spam email gateway 🙂
Nice – I’ll give it a try!
What will be the perl script to download this malware list please?
Regards
How do you unsuscribe Malware? I don’t want it, it is messing up my computer totally!! I want to delete now!!
Remove:
body_checks = regexp:/etc/postfix/mbl-body-deny
Restart postfix and you are done!
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Is it needed to ‘postmap’ the malware file? it complains about many duplicate entries, because i’m using it to block some domains (using ‘From:’ header). I think postmap is not helping in any way with this, because it’s a pcre table, that can’t be postmap’d
Not only is postmap unnecessary, the reload is as well.
I have the following to remove duplicates
This article is outdated (something has changed) or totally wrong.
You cannot postmap regexp.
Just wget the remote file and use
body_checks = regexp:/etc/postfix/mbl-body-deny
http://www.malware.com.br/cgi/submit?action=list_postfix
correct link:
lists.malwarepatrol.net
Yes, like reported by Ro, correct link is :
https://lists.malwarepatrol.net/cgi/getfile?receipt=f1391767429&product=8&list=postfix
Where receipt= should be followed by your personal Malwarepatrol id once registered
Since & characters are present into link, to make it work with wget you have to add double-quotas :
“https://lists.malwarepatrol.net/cgi/getfile?receipt=f1391767429&product=8&list=postfix”
Here’s a simplified script. Insert your own receipt in there, of course 😉
#!/usr/bin/bashcurl -sk 'https://lists.malwarepatrol.net/cgi/getfile?receipt=f1391767429&product=8&list=postfix' | grep -ve '^#' -ve '^$' | sed -e 's/(.*[^MBL-])(MBL-.*)/1/' | sort | uniq -i > /etc/postfix/mbl-body-deny
postmap /etc/postfix/mbl-body-deny
systemctl reload postfix
Why do people keep using postmap? It seems wrong.
postmap /etc/postfix/mbl-body-deny
Should it not be just this added to main.cf:
body_checks = regexp:/etc/postfix/mbl-body-deny