Do you have older QNAP NAS devices that have started failing to update the Antivirus definitions from clamav.net due to the version being too old? Then setup your own virus defintions server and download from there:
To Setup Your Own CLAMDB Virus Definitions Server:
N.B. This is for use on a Linux OS Server - specifically the example commands are for RHEL7.
Use the following website to install the CVD command - https://github.com/Cisco-Talos/cvdupdate
i.e. On a Web server accessible by the QNAP NAS device run the following command:
pip3 install cvdpdate
To set where the clamdb files are stored (and accessible via http from the QNAP NAS Device) use the following command:
cvd config set --dbdir </your/www/path>
To actually DO the updating of the ClamDB files run the following (probably as a daily cron job):
To Setup THE QNAP NAS 'CLIENT' Device:
Logon to your QNAP NAS device via SSH.
Edit /etc/config/crontab and add the following, substituting clamdb.mylocalserver.com for the www hostname of the server you setup above. This changes where the freshclam will download the virus definitions from. It's a cronjob so that the config 'sticks' after a reboot:
0 * * * * echo "DatabaseMirror clamdb.mylocalserver.com" > /etc/config/freshclam.conf && echo "MaxAttempts 2" >> /etc/config/freshclam.conf
Clear out the old definitions from /usr/share/clamav (or copy the folder somewhere else for backup, in case something 'happens'). N.B. this is probably a symbolic link to another writable part of the disk.
Then run a clamav update (N.B: antivirus.sh will start a separate freshclam process):
(or run freshclam -v -u admin, where admin is your admin user)
Now be patient, freshclam can take many minutes to download and update the clamdb files