Tuesday, March 8, 2011

Poor Man's Malware RSS Feed

A customer of mine was in need of a way to be fed well known malware sites on a daily basis so they could feed it into their web inspection proxy. They operated on a blacklist style filtering strategy as opposed to the preferred whitelist methodology.

I figured that a quick and dirty way would be to create for them a daily mail reminder with a list of sites identified as dirty over the last 24 hours. I chose to use some well known malware research sites such as the ones below:

https://spyeyetracker.abuse.ch/blocklist.php?download=domainblocklist
https://zeustracker.abuse.ch/blocklist.php?download=domainblocklist
http://isc.sans.edu/feeds/suspiciousdomains_High.txt


The script I came up with will go out and rip down the data from these lists and store it into a file. Every 24 hours (when combined with cron) it will repeat this and then it will email the recipient any new sites over the last 24 hours.

#!/bin/bash
DATE=`date +%m-%d-%Y`

# Let's grab the daily malware lists and save them into a sorted file...
wget -i /root/Malware/website-urls-to-download.txt --no-check-certificate -O /root/Malware/malwaresites-blacklist-urls.txt
wget http://www.malwaredomainlist.com/hostslist/hosts.txt -O /root/Malware/bad-format-urls.txt
cat /root/Malware/bad-format-urls.txt | cut -c12-100 >> /root/Malware/malwaresites-blacklist-urls.txt
cat /root/Malware/malwaresites-blacklist-urls.txt | sed 's/[ \t]*$//' | sort | uniq > /root/Malware/evil-url-list-$DATE.txt

# We are going to take the sorted file and look for any new URLs, if they appear then we'll mail the changes out
if [ -e /root/Malware/evil-url-list-$DATE.txt ]; then
comm -13 /root/Malware/previous-url-scan.txt /root/Malware/evil-url-list-$DATE.txt > /root/Malware/evil_urls_for_$DATE.txt
sendEmail -f malware_police@somedomain.com -t someone@somedomain.com -u $DATE Daily Evil URL BlockList -o message-file=/root/Malware/evil_urls_for_$DATE.txt -s ex-smtp.somedomain.com:25
fi

# Once we are done with today's sorted file, we are going to save it for later comparison
ln -sf /root/Malware/evil-url-list-$DATE.txt /root/Malware/previous-url-scan.txt



This was done on Linux BackTrack4 distribution.

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