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

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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> On 07/07/2022 23:59 EEST Noel Butler <noel.butler at ausics.net>
wrote:
> 
> 
> 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
Not all CVEs are "that serious". CVE scores are problematic, you can
have a solid 10.0 CVE score that affects practically no one, and you can have a
3.8 CVE that affects ~everyone using the software.

This particular bug requires a quite specific setup, and also provides a
sensible workaround for it.

It will be included in upcoming 2.4 release, we do not currently see any
pressing reason to rush out a CVE patch release for this.

Aki

What? No user serviceable parts inside your car? It's a federal felony to
raise the hood for any reason. You've got to see an authorized dealer or a
professional mechanic for every little thing on a used car because cars are
closed source proprietary and it's illegal to circumvent anything etc. Elon
Musk is hard at work.

On July 7, 2022 12:59:13 PM AKDT, Noel Butler <noel.butler at ausics.net>
wrote:
>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
>
>This Email, including attachments, may contain legally privileged
information, therefore at all times remains confidential and subject to
copyright protected under international law. You may not disseminate this
message without the authors express written authority to do so.   If you are not
the intended recipient, please notify the sender then delete all copies of this
message including attachments immediately. Confidentiality, copyright, and legal
privilege are not waived or lost by reason of the mistaken delivery of this
message.
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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