[Dovecot-news] CVE-2022-30550: Privilege escalation possible in dovecot when similar master and non-master passdbs are used

[Noel Butler]

On 07/07/2022 07:24, Aki Tuomi wrote:

>> On 06/07/2022 16:54 EEST Aki Tuomi via Dovecot-news 
>> <dovecot-news at dovecot.org> wrote:
>> 
>> Affected product: Dovecot IMAP Server
>> Internal reference: DOV-5320
>> Vulnerability type: Improper Access Control (CWE-284)
>> Vulnerable version: 2.2
>> Vulnerable component: submission
>> Report confidence: Confirmed
>> Solution status: Fixed in main
>> Researcher credits: Julian Brook (julezman)
>> Vendor notification: 2022-05-06
>> CVE reference: CVE-2022-30550
>> CVSS: 6.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N)
>> 
>> Vulnerability Details:
>> When two passdb configuration entries exist in Dovecot configuration, 
>> which have the same driver and args settings, the incorrect 
>> username_filter and mechanism settings can be applied to passdb 
>> definitions. These incorrectly applied settings can lead to an 
>> unintended security configuration and can permit privilege escalation 
>> with certain configurations involving master user authentication.
>> 
>> Dovecot documentation does not advise against the use of passdb 
>> definitions which have the same driver and args settings. One such 
>> configuration would be where an administrator wishes to use the same 
>> pam configuration or passwd file for both normal and master users but 
>> use the username_filter setting to restrict which of the users is able 
>> to be a master user.
>> 
>> Risk:
>> If same passwd file or PAM is used for both normal and master users, 
>> it is possible for attacker to become master user.
>> 
>> Workaround:
>> Always authenticate master users from different source than regular 
>> users, e.g. using a separate passwd file. Alternatively, you can use 
>> global ACLs to ensure that only legimate master users have priviledged 
>> access.
>> 
>> Fix:
>> This has been fixed in main branch. See 
>> https://github.com/dovecot/core/compare/7bad6a24%5E..a1022072.patch
> 
> Two small corrections to this CVE notice... The service impacted is of 
> course 'auth' not 'submission', and the version impacted is from 2.2 to 
> 2.3.19.1.
> 
> Aki

I wouldnt exactly call them  " small " corrections

its like saying the left window on your 2020 car can be pushed down 
easily to saying  oh wait its every window and you dont need a key to 
start the engine and btw its all cars from 2010 to 2022

And if its that serious where is the release, thats how dealing with 
CVE's works Aki, not a CVE statement saying go to gitbub.

That said, I'd assume everyone uses a separate db for support teams 
anyway, or I'd hope so/

-- 
Regards,
Noel Butler

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