Headline
CVE-2023-42446: Pow Mnesia cache doesn't invalidate all expired keys on startup
Pow is a authentication and user management solution for Phoenix and Plug-based apps. Starting in version 1.0.14 and prior to version 1.0.34, use of Pow.Store.Backend.MnesiaCache is susceptible to session hijacking as expired keys are not being invalidated correctly on startup. A session may expire when all Pow.Store.Backend.MnesiaCache instances have been shut down for a period that is longer than a session’s remaining TTL. Version 1.0.34 contains a patch for this issue. As a workaround, expired keys, including all expired sessions, can be manually invalidated.
Use of Pow.Store.Backend.MnesiaCache is susceptible to session hijacking as expired keys are not being invalidated correctly on startup. A cache key may become expired when all Pow.Store.Backend.MnesiaCache instances have been shut down for a period that is longer than the keys’ remaining TTL and the expired key won’t be invalidated on startups.
Workarounds
The expired keys, including all expired sessions, can be manually invalidated by running:
:mnesia.sync_transaction(fn -> Enum.each(:mnesia.dirty_select(Pow.Store.Backend.MnesiaCache, [{{Pow.Store.Backend.MnesiaCache, :_, :_}, [], [:"$_"]}]), fn {_, key, {_value, expire}} -> ttl = expire - :os.system_time(:millisecond) if ttl < 0, do: :mnesia.delete({Pow.Store.Backend.MnesiaCache, key}) end) end)
References
15dc525
#713
#714
Related news
Use of `Pow.Store.Backend.MnesiaCache` is susceptible to session hijacking as expired keys are not being invalidated correctly on startup. A cache key may become expired when all `Pow.Store.Backend.MnesiaCache` instances have been shut down for a period that is longer than the keys' remaining TTL and the expired key won't be invalidated on startups. ### Workarounds The expired keys, including all expired sessions, can be manually invalidated by running: ```elixir :mnesia.sync_transaction(fn -> Enum.each(:mnesia.dirty_select(Pow.Store.Backend.MnesiaCache, [{{Pow.Store.Backend.MnesiaCache, :_, :_}, [], [:"$_"]}]), fn {_, key, {_value, expire}} -> ttl = expire - :os.system_time(:millisecond) if ttl < 0, do: :mnesia.delete({Pow.Store.Backend.MnesiaCache, key}) end) end) ``` ### References https://github.com/pow-auth/pow/commit/15dc525be03c466daa5d2119ca7acdec7b24ed17 https://github.com/pow-auth/pow/issues/713 https://github.com/pow-auth/pow/pull/714