Clamav

2/18/18 This wiki is a how-to install ClamAV 0.99.3 on a Raspberry Pi (3) running the latest version of debian (stretch) and all the fun stuff I went through trying to get it to work.

Install

Get the latest source code from: https://www.clamav.net/downloads
Download with wget:

wget https://www.clamav.net/downloads/production/clamav-0.99.4.tar.gz

Untar with:

tar zxf clamav-0.99.4.tar.gz

Enter the clamav directory:

cd clamav-0.99.4/

Create clamav user:

sudo adduser --disabled-login clamav

Download and install prerequisites for compiling:

sudo apt install libssl-dev libpcre3 libpcre3-dev libbz2-dev

Compile ClamAV:

./configure

make

sudo make install

Make a directory for freshclam and change the owner to clamav:

sudo mkdir /usr/local/share/clamav

sudo chown clamav:clamav /usr/local/share/clamav/

Make a copy of the config file:

sudo cp /usr/local/etc/freshclam.conf.sample /usr/local/etc/freshclam.conf

Edit the config file:

sudo nano /usr/local/etc/freshclam.conf

and put a '#' in front of 'example'

then:

sudo ldconfig

Finally run freshclam to download all the virus definitions:

sudo freshclam

Now we will run a little test scan just to make sure everything is working:

sudo clamscan -ri /home

Don't be worried about the infected files just yet. Included in the source code are some test files that contain virus signatures in order to test clamscan. Later we will delete these, but for now leave them alone.

Next create a script that will be run daily to scan your system:

sudo nano /usr/local/sbin/clamscan_daily.sh

And paste this in: (change email addresses as necessary)

#!/bin/bash
LOGFILE="/var/log/clamav/clamav-$(date +'%Y-%m-%d').log";
EMAIL_MSG="Please see the log file attached.";
EMAIL_FROM="clamav@somewhere.com";
EMAIL_TO="someone@gmail.com";

echo "Starting a daily scan";


 clamscan -ri --exclude-dir="^/sys" / >> "$LOGFILE";

 # get the value of "Infected lines"
 MALWARE=$(tail "$LOGFILE"|grep Infected|cut -d" " -f3);

 # if the value is not equal to zero, send an email with the log file attached
 if [ "$MALWARE" -ne "0" ];then
 # using heirloom-mailx below
 echo "$EMAIL_MSG"|mail -a "$LOGFILE" -s "Malware Found On nsserver" -r "$EMAIL_FROM" "$EMAIL_TO";
 fi 

NOTE: if the email has no attachment try changing the mail -a "$LOFILE... to mail -A $LOFILE...

make it executable:

sudo chmod 0755 /usr/local/sbin/clamscan_daily.sh

create dir /var/log/clamav:

sudo mkdir /var/log/clamav

test it with: (a full system scan takes something like 25 min on my RPI 3) This will do a full system scan and email you when it finds infected files (which it will...those test files)

sudo /usr/local/sbin/clamscan_daily.sh

add a crontab entry to run at 1:30am and run freshclam

sudo crontab -e

paste this in:

#run freshclam to get the latest virus definitions
30 01 * * * sudo freshclam > /dev/null

#run clamscan full system check at 1:35am and email on infected files
35 01 * * * sudo /usr/local/sbin/clamscan_daily.sh > dev/null

clear out the stuff we used to build and install clamav:

cd ..

rm clamav-0.99.4.tar.gz

sudo rm -R clamav-0.99.4/

Finally all done. Please note that the log files are NOT setup with logrotate, so they will eventually build up and eat up space...something else for me to figure out :)

References

https://www.clamav.net/
https://www.howtoforge.com/tutorial/configure-clamav-to-scan-and-notify-virus-and-malware/