Security Checklist

This section deals with various steps that you should take to ensure that your AEM installation is secure when deployed. The checklist is meant to be applied from top to bottom.

For more information, see Running AEM in Production Ready Mode.

Enabling the HTTPS transport layer on both author and publish instances is mandatory for having a secure instance.

Ensure that you have installed the latest Security Hotfixes provided by Adobe.

Adobe strongly recommends that after installation you change the password for the privileged AEM admin accounts (on all instances).

These accounts include:

• The AEM admin account
  Once you have changed the password for the AEM admin account, you will need to use the new password when accessing CRX.
• The admin password for the OSGi Web console
  This change will also be applied to the admin account used for accessing the Web console, so you will need to use the same password when accessing that.

These two accounts use separate credentials and having distinct, strong password for each is vital to a secure deployment.

The password for the AEM admin account can be changed via the Granite Operations - Users console.

Here you can edit the admin account and change the password.

Aside from the AEM admin account, failing to change the default password for the OSGi web console password can lead to:

• Exposure of the server with a default password during startup and shutdown (that can take minutes for large servers);
• Exposure of the server when the repository is down/restarting bundle - and OSGI is running.

For more information on changing the web console password, see Changing the OSGi web console admin password below.

You must also change the password used for accessing the Web console. This is done by configuring the following properties of the Apache Felix OSGi Management Console:

User Name and Password, the credentials for accessing the Apache Felix Web Management Console itself.
The password must be changed after the initial installation to ensure the security of your instance.

To do this:

Adobe recommends to define custom error handler pages, especially for 404 and 500 HTTP Response codes in order to prevent information disclosure.

AEM Dispatcher is a critical piece of your infrastructure. Adobe strongly recommend that you complete the dispatcher security checklist.

A standard installation of AEM specifies admin as the user for transport credentials within the default replication agents. Also, the admin user is used to source the replication on the author system.

For security considerations, both should be changed to reflect the particular use case at hand, with the following two aspects in mind:

• The transport user should not be the admin user. Rather, set up a user on the publish system that has only access rights to the relevant portions of the publish system and use that user's credentials for the transport.
  
  You can start from the bundled replication-receiver user and configure this user's access rights to match your situation
  
  
• The replication user or Agent User Id should also not be the admin user, but a user who can only see content that is supposed to be replicated. The replication user is used to collect the content to be replicated on the author system before it is sent to the publisher.
  
  

AEM 6 introduces the new Operations Dashboard, aimed at aiding system operators troubleshoot problems and monitor the health of an instance.

The dashboard also comes with a collection of security health checks. It is recommended you check the status of all the security health checks before going live with your production instance. For more information, consult the Operations Dashboard documentation.

All example content and users (e.g. the Geometrixx project and its components) should be uninstalled and deleted completely on a productive system before making it publicly accessible.

These development OSGi bundles should be uninstalled on both author and publish productive systems before making them accessible.

• Adobe CRXDE Support (com.adobe.granite.crxde-support)
• Adobe Granite CRX Explorer (com.adobe.granite.crx-explorer)
• Adobe Granite CRXDE Lite (com.adobe.granite.crxde-lite)

The AEM Developer Tools for Eclipse deployes the Apache Sling Tooling Support Install (org.apache.sling.tooling.support.install).

This OSGi bundle should be uninstalled on both author and publish productive systems before making them accessible.

AEM 6.1 ships with a mechanism that helps protect agains Cross-Site Request Forgery attacks, called the CSRF Protection Framework. For more information on how to use it, consult the documentation.

To address known security issues with Cross-Site Request Forgery (CSRF) in CRX WebDAV and Apache Sling you need to add configurations for the Referrer filter in order to use it.

The referrer filter service is an OSGi service that allows you to configure:

• which http methods should be filtered
• whether an empty referrer header is allowed
  
• and a white list of servers to be allowed in addition to the server host.

By default, all variations of localhost and the current host names the server is bound to are in the white list.

To configure the referrer filter service:

Some OSGI settings are set by default to allow easier debugging of the application. These need to be changed on your publish and author productive instances to avoid internal information leaking to the public.

For each of the following services the specified settings need to be changed:

• Adobe Granite HTML Library Manager:
  • enable Minify (to remove CRLF and whitespace characters).
  • enable Gzip (to allow files to be gzipped and accessed with one request).
  • disable Debug
  • disable Timing
• Day CQ WCM Debug Filter:
  
  • uncheck Enable
• Day CQ WCM Filter:
  • on publish only, set WCM Mode to "disabled"
    
• Apache Sling Java Script Handler:
  • disable Generate Debug Info
• Apache Sling JSP Script Handler:
  
  • disable Generate Debug Info
  • disable Mapped Content
    

For further details see OSGi Configuration Settings.

When working with AEM there are several methods of managing the configuration settings for such services; see Configuring OSGi for more details and the recommended practices.

A denial of service (DoS) attack is an attempt to make a computer resource unavailable to its intended users. This is often done by overloading the resource; for example:

• With a flood of requests from an external source.
• With a request for more information than the system can successfully deliver.
  For example, a JSON representation of the entire repository.
  
• By requesting a content page with an unlimited number of URLs, The URL can include a handle, some selectors, an extension, and a suffix - any of which can be modified.
  For example, .../en.html can also be requested as:
  • .../en.ExtensionDosAttack
  • .../en.SelectorDosAttack.html
  • .../en.html/SuffixDosAttack
  All valid variations (e.g. return a 200 response and are configured to be cached) will be cached by the dispatcher, eventually leading to a full file system and no service for further requests.

There are many points of configuration for preventing such attacks, here we only discuss those directly related to AEM.

Configuring Sling to Prevent DoS

Sling is content-centric. This means that processing is focused on the content as each (HTTP) request is mapped onto content in the form of a JCR resource (a repository node):

• The first target is the resource (JCR node) holding the content.
• Secondly, the renderer, or script, is located from the resource properties in combination with certain parts of the request (e.g. selectors and/or the extension).

This approach makes Sling very powerful and very flexible, but as always it is the flexibility that needs to be carefully managed.

To help prevent DoS misuse you can:

WebDAV should be disabled on the publish environment. This can be done by stopping the appropriate OSGi bundles.

It is important you protect your users by making sure that you do not expose any personally indetifiable information in the repository users home path.

With AEM 6.1, the way user (also known as authorizable) ID node names are stored is changed with a new implementation of the AuthorizableNodeName interface. The new interface will no longer expose the user ID in the node name, but will generate a random name instead.

No configuration needs to be performed in order to enable it, as this is the default way of generating authorizable IDs in AEM 6.1.

Although not recommended, you can disable it in case you need the old implementation for backwards compatibility with your exsiting applications. In order to do this, you need to delete the
Apache Jackrabbit Oak Random Authorizable Node Name OSGi configuration from the Web Console.

To prevent clickjacking we recommend that you configure your webserver to provide the X-FRAME-OPTIONS HTTP header set to SAMEORIGIN.

For more information on clickjacking please see the OWASP site.

Adobe strongly recommends to perform a penetration test of your AEM infrastructure before going on production.

It is critical that new development are following the Security Best Practices to ensure your AEM environement stays safe.