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GHSA-q82v-h4rq-5c86
No affected components available
Impact
A vulnerability has been identified within Rancher Manager where a missing server-side validation on the .username field in Rancher can allow users with update permissions on other User resources to cause denial of access for targeted accounts. Specifically:
- Username takeover: A user with permission to update another user’s resource can set its
.usernameto "admin", preventing both the legitimate admin and the affected user from logging in, as Rancher enforces uniqueness at login time. - Account lockout: A user with update permissions on the admin account can change the admin’s username, effectively blocking administrative access to the Rancher UI.
This issue enables a malicious or compromised account with elevated update privileges on User resources to disrupt platform administration and user authentication.
Note: The users with these permissions to modify accounts and resources are considered as privileged users. For more information, please consult Rancher Manger’s documentation about global permissions.
Please consult the associated MITRE ATT&CK - Technique - Account Access Removal for further information about this category of attack.
Patches
This vulnerability is addressed by adding a new check in the webhook which blocks modifying usernames after it has been set. If it's empty then the username can be set to a username not already in use, but after that it is immutable.
Patched versions of Rancher include releases v2.12.2, v2.11.6, v2.10.10 and v2.9.12.
Workarounds
If you can't upgrade to a fixed version, please make sure that you are only granting update permissions on users’ related resources to trusted users.
References
If you have any questions or comments about this advisory:
- Reach out to the SUSE Rancher Security team for security related inquiries.
- Open an issue in the Rancher repository.
- Verify with our support matrix and product support lifecycle.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs high-level or administrative privileges. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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