Na verdade, tudo é normal. Não há problema
Porque agora o ClamAV tem um daemon. O daemon faz as atualizações. Então, se quisermos fazer atualizações manualmente, precisamos parar o daemon primeiro.
$ tail /var/log/clamav/freshclam.log
Thu Nov 10 19:55:59 2016 -> WARNING: Can't query current.cvd.clamav.net
Thu Nov 10 19:55:59 2016 -> WARNING: Invalid DNS reply. Falling back to HTTP mode.
Thu Nov 10 19:55:59 2016 -> Reading CVD header (main.cvd): Thu Nov 10 19:55:59 2016 -> WARNING: Can't get information about db.local.clamav.net: Temporary failure in name resolution
Thu Nov 10 19:55:59 2016 -> WARNING: Can't read main.cvd header from db.local.clamav.net (IP: )
Thu Nov 10 19:55:59 2016 -> Trying again in 5 secs...
Thu Nov 10 19:56:04 2016 -> ClamAV update process started at Thu Nov 10 19:56:04 2016
Thu Nov 10 19:56:04 2016 -> main.cvd is up to date (version: 57, sigs: 4218790, f-level: 60, builder: amishhammer)
Thu Nov 10 19:56:04 2016 -> daily.cld is up to date (version: 22511, sigs: 853831, f-level: 63, builder: neo)
Thu Nov 10 19:56:04 2016 -> bytecode.cld is up to date (version: 283, sigs: 53, f-level: 63, builder: neo)
Thu Nov 10 19:56:04 2016 -> --------------------------------------
$ sudo service clamav-freshclam stop
$ sudo freshclam
ClamAV update process started at Thu Nov 10 20:20:26 2016
main.cvd is up to date (version: 57, sigs: 4218790, f-level: 60, builder: amishhammer)
daily.cld is up to date (version: 22511, sigs: 853831, f-level: 63, builder: neo)
bytecode.cld is up to date (version: 283, sigs: 53, f-level: 63, builder: neo)
$ tail /var/log/clamav/freshclam.log
Thu Nov 10 19:56:04 2016 -> main.cvd is up to date (version: 57, sigs: 4218790, f-level: 60, builder: amishhammer)
Thu Nov 10 19:56:04 2016 -> daily.cld is up to date (version: 22511, sigs: 853831, f-level: 63, builder: neo)
Thu Nov 10 19:56:04 2016 -> bytecode.cld is up to date (version: 283, sigs: 53, f-level: 63, builder: neo)
Thu Nov 10 19:56:04 2016 -> --------------------------------------
Thu Nov 10 20:18:57 2016 -> Update process terminated
Thu Nov 10 20:20:26 2016 -> --------------------------------------
Thu Nov 10 20:20:26 2016 -> ClamAV update process started at Thu Nov 10 20:20:26 2016
Thu Nov 10 20:20:26 2016 -> main.cvd is up to date (version: 57, sigs: 4218790, f-level: 60, builder: amishhammer)
Thu Nov 10 20:20:26 2016 -> daily.cld is up to date (version: 22511, sigs: 853831, f-level: 63, builder: neo)
Thu Nov 10 20:20:26 2016 -> bytecode.cld is up to date (version: 283, sigs: 53, f-level: 63, builder: neo)
$ sudo service clamav-freshclam start