The Tor Project has updated its browser after the discovery of a bug with more than dangerous repercussions for user privacy. URLs based on onion services version 2 should migrate to version 3 before September 2021.

A recent update of the Tor Browser to version 10.0.18 has enabled several bugs to be corrected, including a rather serious vulnerability for users, French IT news site Le Monde Informatique reports. As a matter of fact, this bug, which is based on version 2 of its onion services, enabled some sites to track users from the applications installed on their devices.

Tor Browser running on Ubuntu Linux

Tor Browser running on Ubuntu Linux. Image courtesy of Wikimedia Commons.

The vulnerability tracked users via their browsers, enabling any website or government to discover a user’s actual IP address, which is contrary to the basic principle of the Tor project. URLs actually benefit from a security gain with version 3 of onion services. This is due to the fact that they use “cleaner” code with stronger cryptography which is proving to be less susceptible to brute force attacks due to its complexity.

URLs under onion services V2 no longer supported from 15 July

The project also announced it would start to deprecate URLs under onion services version 2 by initially advising the operators and clients that access them. With effect from 15 July, Tor will no longer support V2 URLs V2 and support for them will be removed from the browser codebase.

So as to ensure that each user and website administrator is well aware of this change, a message will be displayed “when visiting sites which are still using V2 URLs advising they will shortly be deprecated and the site will be inaccessible unless it is updated to version 3 of onion services“.