An update. Turns out for our setup we had to do the following:
- Give the apache user the additional group clamscan. The reason for this is to allow the apache user to execute clamdscan via exec. We were getting the error 'Could not connect to clamd on LocalSocket' and this was resolved with that change.
- Enable LocalSocketGroup in clamd.conf with the group clamscan.
- Change the ClamAV commands in ilias.ini.php to include the parameter '--fdpass'. The reason for --fdpass is to allow clamav access to the files that are uploaded.
- scancommand = "/usr/bin/clamdscan --fdpass"
- cleancommand = "/usr/bin/clamdscan --fdpass --remove=yes"