Further actions

Hosting environment

A system administrator is usually responsible for the entirety of an IT infrastructure. This includes several services (e.g. web server, mail server, database server, SSH, FTP, DNS, etc.) on one or on several servers. If one component is compromised, it is likely that this opens holes to attack other services.

As a consequence, it is desired to secure all components of an IT infrastructure and keep them up-to-date and secure with only a little or no dependencies to other system. It is also wise to abandon services which are not necessarily required (e.g. an additional database server, DNS server, IMAP/POP3 server, etc.). In short words: keep your hosting environment as slim as possible for performance and security purposes.

Events in log files

Login attempts to the TYPO3 backend, which are unsuccessful, result in a server response to the client with HTTP code 401 (“Unauthorized”). Due to the fact that this incident is logged in the web server’s error log file, it can be handled by external tools, such as fail2ban.

Defending against Clickjacking

Clickjacking, also knows as user interface (UI) redress attack or UI redressing, is an attack scenario where an attacker tricks a web user into clicking on a button or following a link different from what the user believes he/she is clicking on. This attack can be typically achieved by a combination of stylesheets and iframes, where multiple transparent or opaque layers manipulate the visual appearance of a HTML page.

To protect the backend of TYPO3 CMS against this attack vector, a HTTP header X-Frame-Options is sent, which prevents embedding backend pages in an iframe on domains different than the one used to access the backend. The X-Frame-Options header has been officially standardized as RFC 7034.

System administrators should consider enabling this feature at the frontend of the TYPO3 website, too. A configuration of the Apache web server would typically look like the following:

<IfModule mod_headers.c>
  Header always append X-Frame-Options SAMEORIGIN

The option SAMEORIGIN means, that the page can only be displayed in a frame on the same origin as the page itself. Other options are DENY (page cannot be displayed in a frame, regardless of the site attempting to do so) and ALLOW-FROM [uri] (page can only be displayed in a frame on the specified origin).

Please understand that detailed descriptions of further actions on a server-level and specific PHP security settings are out of scope of this document. The TYPO3 Security Guide focuses on security aspects of TYPO3.