Automating Linux Anti-Virus Using ClamAv and Cron

Clam AntiVirus (ClamAV) is a free, cross-platform antivirus tool-kit able to detect many types of malicious software, including viruses. One of its main uses is on mailservers as a server-side email virus scanner. The application was developed for Unix and has third party versions available for AIX, BSD, HP-UX, LINUX, MAC OS X, openVMS, OSF (Tru64) and Solaris.Here in this section we will try to automate the entire Process of clamAv using cronjob.We are using Red-hat enterprises Linux platform to test this.

Step 1: Install ClamAV

We can use yum command to install clamav in the server.

# yum install clamav clamav-db clamd

Try to start the clamav by typing the command below.

# /etc/init.d/clamd start

This automatically sets up a daily cron job which runs fresh clam to update virus definitions.

Step 2 : Create new cron jobs to run daily virus scans

First we need to create a file clamscan_daily in cron.daily folder.It will help us to paste our script in this file,all the files or scripts in this folder will run automatically daily.

Create a clamscan_daily file in the folder cron.daily

#vi /etc/cron.daily/clamscan_daily

Paste the below script in the file and save.


# email subject


# Email To ?


# Log location


check_scan () {

# Check the last set of results. If there are any “Infected” counts that aren’t zero, we have a problem.

if [ `tail -n 12 ${LOG} | grep Infected | grep -v 0 | wc -l` != 0 ]


EMAILMESSAGE=`mktemp /tmp/virus-alert.XXXXX`

echo “To: ${EMAIL}” >> ${EMAILMESSAGE}

echo “From:” >> ${EMAILMESSAGE}

echo “Subject: ${SUBJECT}” >> ${EMAILMESSAGE}

echo “Importance: High” >> ${EMAILMESSAGE}

echo “X-Priority: 1” >> ${EMAILMESSAGE}

echo “`tail -n 50 ${LOG}`” >> ${EMAILMESSAGE}

sendmail -t < ${EMAILMESSAGE}



clamscan -r / –exclude-dir=/sys/ –quiet –infected log=${LOG}

Step 3 : set-up proper permission to the file

#chmod +x /etc/cron.hourly/clamscan_hourly

This steps will help to setup automation of clamav in the server and reports are send directly to the email given in the script.

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