Authentication And Authorization In The CGIs


Throughout these instructions I will be assuming that you are running the Apache web server on your machine. If you are running some other web server, you will have to make some adjustments.


Throughout these instructions I will be using the following terms, so you should understand what they mean...


Setting up authenticated users
Enabling authentication/authorization functionality in the CGIs
Default permissions to CGI information
Granting additional permissions to CGI information
Authentication on secure web servers

Setting Up Authenticated Users

If you haven't done so already, you'll need to add the appropriate entries to your web server config file to enable basic authentication for the CGI and HTML portions of the Nagios web interface. Instructions for doing so can be found here.

Now that you've configured your web server to require authentication for the Nagios web interface, you'll need to specify who has access. This is done by using the htpasswd command supplied with Apache.

Running the following command will create a new file called htpasswd.users in the /usr/local/nagios/etc directory. It will also create an username/password entry for nagiosadmin. You will be asked to provide a password that will be used when nagiosadmin authenticates to the web server.

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Continue adding more users until you've created an account for everyone you want to access the CGIs. Use the following command to add additional users, replacing <username> with the actual username you want to add. Note that the -c option is not used, since you already created the initial file.

htpasswd /usr/local/nagios/etc/htpasswd.users <username>

Okay, so you're done with the first part of what needs to be done. At this point you should be prompted for a username and password if you point your web browser to the Nagios web interface. If you have problems getting user authentication to work at this point, read your webserver documentation for more info.

Enabling Authentication/Authorization Functionality In The CGIs

The next thing you need to do is make sure that the CGIs are configured to use the authentication and authorization functionality in determining what information and/or commands users have access to. This is done be setting the use_authentication variable in the CGI configuration file to a non-zero value. Example:


Okay, you're now done with setting up basic authentication/authorization functionality in the CGIs.

Default Permissions To CGI Information

So what default permissions do users have in the CGIs by default when the authentication/authorization functionality is enabled?

CGI Data Authenticated Contacts* Other Authenticated Users*
Host Status Information Yes No
Host Configuration Information Yes No
Host History Yes No
Host Notifications Yes No
Host Commands Yes No
Service Status Information Yes No
Service Configuration Information Yes No
Service History Yes No
Service Notifications Yes No
Service Commands Yes No
All Configuration Information No No
System/Process Information No No
System/Process Commands No No

Authenticated contacts* are granted the following permissions for each service for which they are contacts (but not for services for which they are not contacts)...

Authenticated contacts* are granted the following permissions for each host for which they are contacts (but not for hosts for which they are not contacts)...

It is important to note that by default no one is authorized for the following...

You will undoubtably want to access this information, so you'll have to assign additional rights for yourself (and possibly other users) as described below...

Granting Additional Permissions To CGI Information

You can grant authenticated contacts or other authenticated users permission to additional information in the CGIs by adding them to various authorization variables in the CGI configuration file. I realize that the available options don't allow for getting really specific about particular permissions, but its better than nothing..

Additional authorization can be given to users by adding them to the following variables in the CGI configuration file...

CGI Authorization Requirements

If you are confused about the authorization needed to access various information in the CGIs, read the Authorization Requirements section for each CGI as described here.

Authentication On Secured Web Servers

If your web server is located in a secure domain (i.e., behind a firewall) or if you are using SSL, you can define a default username that can be used to access the CGIs. This is done by defining the default_user_name option in the CGI configuration file. By defining a default username that can access the CGIs, you can allow users to access the CGIs without necessarily having to authenticate to the web server.. You may want to use this to avoid having to use basic web authentication, as basic authentication transmits passwords in clear text over the Internet.

Important: Do not define a default username unless you are running a secure web server and are sure that everyone who has access to the CGIs has been authenticated in some manner! If you define this variable, anyone who has not authenticated to the web server will inherit all rights you assign to this user!