Currently, MediaWiki software allows permissioned users to stop a person from performing actions (e.g. editing, creating pages, messaging other users) by blocking their username, IP address, or IP range. Block evasions are simple on Wikimedia wikis.
The Anti-Harassment Tools team at the Wikimedia Foundation has been tasked with looking to modernize our blocking tools to make blocks more effective and less easy to evade. The impetus is for Long-Term-Abuse but this project may be further reaching. There will be no silver bullet but it is the responsibility of the WMF to install safeguards for our users, our staff, and the content that we host.
Browser fingerprints are being investigated in T213351 but there are alternatives that we should explore. Please use this task to discuss alternatives.