Redmine

Also, I suggest to deny login if search by autologin within Token table returned 2 or more records - it allows to prevent and troubleshot possible errors in future.

I never experienced

We suspect it is due to process forking which leads to random sequence seed inherited from parent process so two processes continue working with the same sequence.

ActiveSupport::SecureRandom is now used to generate tokens

Thanks, it is what we were going to suggest!

Small example from our developers

irb(main):004:0> rand(50)
=> 9
irb(main):005:0> fork { puts rand(50) }
37
=> 22831
irb(main):006:0> rand 50
=> 37

Also, you could check your DB to ensure you have really never affected by this vulnerability

select value, count(*) from tokens group by value having count(*) > 1

That's what I did when I said that I never experienced this issue.

Jean-Philippe Lang wrote:

That's what I did when I said that I never experienced this issue.

Probably you are not using mod_passenger. If you started several predefined processes (without mod_passenger) then random sequence had their own seeds and their own random sequences.

mod_passenger do forks and these inherit parent seed (see post #4) - it is key factor to reproduce problem.