MediaWiki, the software behind projects like Wikipedia and Wiktionary is software written with an eye for security. The practices that are employed prove that security is taken seriously. The point is that people do not always understand what security means and what security is provided.
Many of the MediaWiki implementations allow everybody to create and change articles. This is a conscious decision, it is part of the formula and consequently this is not a problem from a security point of view. As a consequence the problem of maintaining quality content and preventing people vandalising the content, is a management problem. The tools to manage this problem are diverse but many tools that are considered security tools are usable.
Often vandals do not know that what they do is useless. Often people add links to all kinds of websites in order to increase their Google-rating. The MediaWiki software indicates to the Google crawler NOT to include external websites for its ratings.
Blocking IP-ranges and users because of persistent vandalism is one. Trusting logged in users more than anonymous users is another. There are many Wikimedia projects and all of them still have at present their own users. In Februari, it is planned to develop single signon for the Wikimedia projects. Single login has been on the wishlist of many of the people who are active on multiple projects.
With single login, in essence a management issue with security implications, it becomes feasible to use this as a stepping stone for the implimentation of security features that help with the management of vandalism.
The feature that I would love best is to differentiate the strength of authentication based on where a user comes from. When a user comes from a school with a history of vandalism, it makes sense not to allow anonymous edits. There are many of these types of soft security measures possible.
On mailing lists about Wikimedia, there was talk about a patch that allows for logging in users who authenticate themselves with OpenID. The interesting thing was that people had two issues with this; first it would not allow me to use my MediaWiki ID as an OpenID. The second is that to some extend OpenID is going to fit into the YADIS framework (Yet Another Decentralized Identity Interoperability System).
Yadis is interesting because it is linked to the eXtensible Resource Identifier or XRI, a standard that is developped by OASIS. It is also linked to the W3C (YASB - yet another standard body :) ).
In the end it comes back to standards; when the WMF would support twoway YADIS authentication, it makes for a VERY relevant implementation of security related functionality. This could provide for better management in the fight against vandalism. It is however important that it is a standard that we provide. That is why I am of the opinion that the WMF should support standards.