A critical security advisory has been issued by VMware to administrators, urging them to remove a deprecated authentication plugin that is vulnerable to severe security threats. The Enhanced Authentication Plugin (EAP), which provided seamless login capabilities to vSphere’s management interfaces, is susceptible to authentication relay and session hijack attacks due to two unpatched security vulnerabilities.
The two vulnerabilities, known as CVE-2024-22245 and CVE-2024-22250, pose significant risks to Windows domain environments. CVE-2024-22245 allows a malicious actor to relay Kerberos service tickets, potentially leading to the takeover of privileged EAP sessions, with a CVSS score of 9.6. On the other hand, CVE-2024-22250, scored at 7.8, enables an attacker with local access to hijack an EAP session initiated by a privileged domain user.
These vulnerabilities were discovered by Ceri Coburn from Pen Test Partners and reported to VMware, which has acknowledged the critical nature of these flaws.
The Arbitrary Authentication Relay vulnerability (CVE-2024-22245) allows a malicious actor to install EAP on a target domain user’s web browser, fooling them into requesting and transmitting service tickets for any Active Directory Service Principal Name (SPN). This vulnerability has a maximum CVSSv3 base score of 9.6, falling into the Critical severity range.
Additionally, the Session Hijack vulnerability (CVE-2024-22250) allows unauthorized users to hijack sessions, posing a maximum CVSSv3 base score of 7.8, which VMware has also classified as of critical severity. A privileged domain user on the same machine can start a privileged EAP session, but an attacker with unprivileged local access to Windows can hijack it.
The deprecated EAP is not installed by default and is not part of VMware’s core products like vCenter Server, ESXi, or Cloud Foundation. However, it may have been manually installed on Windows workstations used for administrative tasks. These vulnerabilities in the EAP can put organizations at risk of unauthorized access and control over their virtualized environments, potentially leading to data breaches and system disruptions.
In response to these critical vulnerabilities, VMware has decided not to patch the EAP due to its deprecation and the associated security risks of bypassing modern web browser security features. Instead, VMware recommends completely removing the EAP to secure systems against potential attacks. The company has provided PowerShell commands to uninstall the plugin and the associated Windows service. Additionally, VMware suggests using other authentication methods such as Active Directory over LDAPS, Microsoft Active Directory Federation Services (ADFS), Okta, and Microsoft Entra ID24 as alternatives to the vulnerable plugin.
The advisory underscores the importance of maintaining up-to-date and secure authentication mechanisms. Organizations using the EAP should take immediate action to remove the plugin and switch to supported authentication methods to protect their environments from potential exploitation. The risks posed by these vulnerabilities highlight the need for continued vigilance and proactive measures to ensure the security of virtualized environments.
In conclusion, the security flaws in the Enhanced Authentication Plugin (EAP) present a significant threat to organizations using this deprecated authentication method. Administrators are strongly advised to remove the plugin and transition to more secure authentication mechanisms to safeguard their virtualized environments against potential attacks.