CVE-2024-10306 is an authorization vulnerability identified in mod_proxy_cluster version 1.3.17, a module used for managing load balancing clusters in web server environments. The root cause is the incorrect use of the <Directory> directive in the configuration to restrict access by IP address, which does not enforce the intended access controls. The correct directive to use is <Location>, which properly restricts access based on IP addresses using the 'Require ip IP_ADDRESS' directive. Because of this misconfiguration, any user with access to the host running mod_proxy_cluster can send MCMP (Mod Cluster Management Protocol) requests to manipulate the cluster nodes—adding, removing, or updating them. This manipulation can compromise the integrity of the load balancing configuration, potentially redirecting traffic or causing misrouting. The vulnerability does not require user interaction but does require at least low-level privileges on the host, meaning that attackers must have some access to the internal network or host environment. The affected host is not intended to be exposed to the public internet, as it does not serve general traffic, but improper network segmentation or firewall misconfigurations could expose it. The CVSS v3.1 base score is 5.4 (medium), reflecting the network attack vector, low attack complexity, low privileges required, no user interaction, and limited impact on confidentiality and integrity without affecting availability. No public exploits are known at this time, but the vulnerability poses a risk to the integrity and confidentiality of load balancing configurations in affected environments.

For European organizations, exploitation of CVE-2024-10306 could lead to unauthorized modification of load balancing cluster configurations, potentially redirecting or intercepting internal traffic, which may expose sensitive data or disrupt internal application routing. While availability is not directly impacted, the integrity compromise could facilitate further lateral movement or privilege escalation within the network. Organizations relying on mod_proxy_cluster 1.3.17 for internal load balancing may face risks of unauthorized access or manipulation if network segmentation is insufficient. This is particularly concerning for sectors with strict data protection requirements, such as finance, healthcare, and government, where internal traffic confidentiality and integrity are critical. The vulnerability could also undermine trust in internal infrastructure and complicate incident response if attackers manipulate cluster nodes to evade detection or redirect traffic through malicious proxies.

European organizations should immediately audit their mod_proxy_cluster configurations to ensure the <Directory> directive is replaced with the <Location> directive for access control, enforcing IP-based restrictions correctly. Network segmentation should be reviewed to ensure that hosts running mod_proxy_cluster are not accessible from untrusted networks, including the public internet. Implement strict firewall rules to limit access to the management interfaces of mod_proxy_cluster only to authorized IP addresses and administrative personnel. Regularly update mod_proxy_cluster to the latest version once patches addressing this vulnerability are released. Additionally, monitor MCMP traffic for unusual patterns that could indicate exploitation attempts. Employ host-based intrusion detection systems to alert on unauthorized configuration changes. Finally, conduct internal penetration testing to verify that access controls are effective and that the management interfaces are not exposed beyond intended boundaries.