Ubuntu: Unmet dependencies

Hab ein kleines Problem mit meinem Ubuntu 14.04 vServer:

Code:

user@server:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 modsecurity-crs : Depends: libapache2-modsecurity (>= 2.6.0) but it is not installed
E: Unmet dependencies. Try using -f.

Code:

user@server:~$ sudo dpkg --configure -a
dpkg: dependency problems prevent configuration of modsecurity-crs:
modsecurity-crs depends on libapache2-modsecurity (>= 2.6.0); however:
  Package libapache2-modsecurity is not installed.

dpkg: error processing package modsecurity-crs (--configure):
dependency problems - leaving unconfigured
Setting up libapache2-mod-security2 (2.7.7-2) ...
apache2_invoke: Enable module security2
 * Restarting web server apache2                                         [ OK ]
Errors were encountered while processing:
 modsecurity-crs

Jemand einen Tipp? apt-get -f install hat nichts gebracht.