Hi I'd like to be able to auto update rkhunter when upgrades happen automatically, but I can't seem to find a way to do this. I'd not want this to happen after a manual install via apt-get though or anything, just when the auto updates occur. Any ideas?
1) If you installed rkhunter via apt-get, I believe you need to enable AutomaticSecurityUpdates.
2) If you compiled & installed rkhunter from tar.gz, you need to run:
sudo rkhunter --versioncheck
However, I don't see how one can link this back to Ubuntu update process.
3) Now if by updating rkhunter you mean to update the signature database on updating Ubuntu packages as documented here:
To run rkhunter --propupd, automatic after software updates, add the line APT_AUTOGEN="yes" to /etc/default/rkhunter (this gets read by /etc/apt/apt.conf.d/90rkhunter)