The stock mod_auth_mysql package in Ubuntu is not able to authenticate against the phpass password hashes stored in the WordPress database.
There seems to be a patch lying around to enable phpass authentication in mod_auth_mysql. Its inclusion in mod_auth_mysql has been requested a long time ago, and again more recently, but for one reason or another it has been declined. Inclusion of the patch into the Debian package has also been requested.
Thanks to Peter Lamberg, there are good instructions around on how to apply the patch and enable it. I’ve made available a pre-compiled 64-bit package here: Continue reading Apache HTTP authentication against WordPress password database