#VU89587 Improper Authentication in OpenSSH - CVE-2023-51767

Vulnerability identifier: #VU89587

Vulnerability risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2023-51767

CWE-ID: CWE-287

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
OpenSSH
Server applications / Remote management servers, RDP, SSH

Vendor: OpenSSH

Description

The vulnerability allows a local user to bypass authentication process.

The vulnerability exists due to an error in when processing authentication requests. A local user can bypass authentication process and gain unauthorized access to the application by conducting a row hammer attack against the mm_answer_authpassword integer value to flip a single bit.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OpenSSH: All versions

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External links
https://arxiv.org/abs/2309.02545
https://github.com/openssh/openssh-portable/blob/8241b9c0529228b4b86d88b1a6076fb9f97e4a99/monitor.c#L878
https://github.com/openssh/openssh-portable/blob/8241b9c0529228b4b86d88b1a6076fb9f97e4a99/auth-passwd.c#L77
https://bugzilla.redhat.com/show_bug.cgi?id=2255850
https://access.redhat.com/security/cve/CVE-2023-51767
https://ubuntu.com/security/CVE-2023-51767
https://security.netapp.com/advisory/ntap-20240125-0006/

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.