Bug 2108205 (CVE-2022-32744)

Summary: CVE-2022-32744 samba: AD users can forge password change requests for any user
Product: [Other] Security Response Reporter: Mauro Matteo Cascella <mcascell>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: abokovoy, anoopcs, asn, dkarpele, gdeschner, iboukris, jarrpa, jstephen, lmohanty, madam, pfilipen, rhs-smb, sbose, security-response-team, ssorce
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: samba 4.16.4, samba 4.15.9, samba 4.14.14 Doc Type: ---
Doc Text:
A flaw was found in Samba. The KDC accepts kpasswd requests encrypted with any key known to it. By encrypting forged kpasswd requests with its own key, a user can change other users' passwords, enabling full domain takeover.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2022-08-30 14:55:50 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2111731    
Bug Blocks: 2095310, 2095313    

Description Mauro Matteo Cascella 2022-07-18 15:22:17 UTC 
As per samba upstream advisory:

Tickets received by the kpasswd service were decrypted without specifying that only that service's own keys should be tried. By setting the ticket's server name to a principal associated with their own account, or by exploiting a fallback where known keys would be tried until a suitable one was found, an attacker could have the server accept tickets encrypted with any key, including their own.

A user could thus change the password of the Administrator account and gain total control over the domain. Full loss of confidentiality and integrity would be possible, as well as of availability by denying users access to their accounts.

In addition, the kpasswd service would accept tickets encrypted by the krbtgt key of an RODC, in spite of the fact that RODCs should not have been able to authorise password changes.
Comment 1 Sandipan Roy 2022-07-28 04:08:43 UTC 
Created samba tracking bugs for this issue:

Affects: fedora-all [bug 2111731]
Comment 2 Product Security DevOps Team 2022-08-30 14:55:47 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2022-32744