Adding the following rule to /etc/apparmor.d/usr.sbin.clamd resolves the problem apparently
/var/spool/MIMEDefang/** r,
Scanning works:
Aug 19 02:04:31 utest-nns32 mimedefang.pl[4544]: MDLOG,p7IN4UXO005515,virus,Eicar-Test-Signature,172.16.21.1,<email address hidden>,<email address hidden>,[TESTMAIL] eicar test mail
Aug 19 02:04:31 utest-nns32 mimedefang.pl[4544]: Discarding because of virus Eicar-Test-Signature
Aug 19 02:04:31 utest-nns32 mimedefang.pl[4544]: filter: p7IN4UXO005515: discard=1
Adding the following rule to /etc/apparmor. d/usr.sbin. clamd resolves the problem apparently
/var/spool/ MIMEDefang/ ** r,
Scanning works:
Aug 19 02:04:31 utest-nns32 mimedefang. pl[4544] : MDLOG,p7IN4UXO0 05515,virus, Eicar-Test- Signature, 172.16. 21.1,<email address hidden>,<email address hidden>,[TESTMAIL] eicar test mail pl[4544] : Discarding because of virus Eicar-Test- Signature pl[4544] : filter: p7IN4UXO005515: discard=1
Aug 19 02:04:31 utest-nns32 mimedefang.
Aug 19 02:04:31 utest-nns32 mimedefang.