CVE-2022-0336

The Samba AD DC includes checks when adding service principals names (SPNs) to an account to ensure that SPNs do not alias with those already in the database. Some of these checks are able to be bypassed if an account modification re-adds an SPN that was previously present on that account, such as one added when a computer is joined to a domain. An attacker who has the ability to write to an account can exploit this to perform a denial-of-service attack by adding an SPN that matches an existing service. Additionally, an attacker who can intercept traffic can impersonate existing services, resulting in a loss of confidentiality and integrity.

Weakness

During installation, installed file permissions are set to allow anyone to modify those files.

Affected Software

Potential Mitigations

• Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
• Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/1.html
• https://cwe.mitre.org/data/definitions/127.html
• https://cwe.mitre.org/data/definitions/81.html

References

• https://access.redhat.com/security/cve/CVE-2022-0336
• https://bugzilla.redhat.com/show_bug.cgi?id=2046134
• https://bugzilla.samba.org/show_bug.cgi?id=14950
• https://github.com/samba-team/samba/commit/1a5dc817c0c9379bbaab14c676681b42b0039a3c
• https://github.com/samba-team/samba/commit/c58ede44f382bd0125f761f0479c8d48156be400
• https://security.gentoo.org/glsa/202309-06
• https://www.samba.org/samba/security/CVE-2022-0336.html