Pow Mnesia cache doesn't invalidate all expired keys on startup

2023-09-1917:00:08

Google

osv.dev

pow

mnesia

cache

session hijacking

expiration

invalidation

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS

0.001

Percentile

23.9%

JSON

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 -&gt;
  Enum.each(:mnesia.dirty_select(Pow.Store.Backend.MnesiaCache, [{{Pow.Store.Backend.MnesiaCache, :_, :_}, [], [:"$_"]}]), fn {_, key,  {_value, expire}} -&gt;
    ttl = expire - :os.system_time(:millisecond)
    if ttl &lt; 0, do: :mnesia.delete({Pow.Store.Backend.MnesiaCache, key})
  end)
end)