Should the developers bring back Vanguards support to Whonix?
From the limited information The Tor Project has, we believe that one user of the long-retired application Ricochet was fully de-anonymized through a guard discovery attack. This was possible, at the time, because the user was using a version of the software that neither had Vanguards-lite, nor the vanguards addon, which were introduced to protect users from this type of attack. This protection exists in Ricochet-Refresh, a maintained fork of the long-retired project Ricochet, since version 3.0.12 released in June of 2022.
Vanguards-lite, released in Tor 0.4.7, protects against the possibility of combining an adversary-induced circuit creation with circuit-based covert channel to obtain a malicious middle relay confirmed to be next to the user’s Guard. Once the Guard is obtained, netflow connection times can be used to find the user of interest. In this case, the netflow attack could proceed quickly, because the attacker was able to determine when the user was online and offline due to their Onion Service descriptor being available, combined with the low number of users on the discovered Guard.