CVE-2024-32663 is a vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) and CWE-770 (Allocation of Resources Without Limits or Throttling) affecting the Suricata network security monitoring engine. Suricata versions 6.0.0 through 6.0.18 and 7.0.0 through 7.0.4 improperly handle HTTP/2 traffic, where even a small amount of such traffic can cause the application to consume excessive memory resources. This occurs due to the HTTP/2 parser allocating large amounts of memory based on the max-table-size parameter, which by default is set to 65536. Attackers can exploit this by sending crafted HTTP/2 packets that trigger large memory allocations, leading to resource exhaustion and denial of service (DoS). The vulnerability is remotely exploitable without requiring authentication or user interaction, making it a significant risk for network perimeter defenses and monitoring systems. The issue has been addressed in Suricata versions 7.0.5 and 6.0.19. Workarounds include disabling the HTTP/2 parser entirely or reducing the max-table-size parameter to limit memory usage. Since Suricata is widely used in intrusion detection and prevention systems, this vulnerability can impact the availability of critical network security functions if exploited.

For European organizations, this vulnerability poses a significant risk to the availability of network security monitoring and intrusion detection capabilities. Suricata is commonly deployed in enterprise networks, government agencies, and critical infrastructure sectors across Europe. An attacker exploiting this vulnerability could cause Suricata instances to consume excessive memory, leading to crashes or degraded performance, effectively resulting in denial of service. This could blind security teams to ongoing attacks or network anomalies, increasing the risk of undetected breaches. Financial institutions, telecommunications providers, and public sector entities that rely heavily on Suricata for real-time threat detection are particularly vulnerable. The disruption could also affect compliance with regulatory requirements for network security monitoring under frameworks like GDPR and NIS Directive. Given the remote and unauthenticated nature of the exploit, the threat landscape includes opportunistic attackers scanning for vulnerable Suricata deployments, as well as targeted attacks against high-value European organizations.

1. Immediately upgrade Suricata to version 7.0.5 or 6.0.19 where the vulnerability is patched. 2. If immediate upgrade is not feasible, disable the HTTP/2 parser in Suricata configuration to prevent processing of HTTP/2 traffic. 3. Alternatively, reduce the `app-layer.protocols.http2.max-table-size` parameter from its default 65536 to a lower value to limit memory allocation during HTTP/2 parsing. 4. Monitor Suricata instances for abnormal memory usage or crashes that could indicate exploitation attempts. 5. Implement network-level controls to limit or inspect HTTP/2 traffic from untrusted sources. 6. Maintain up-to-date intrusion detection signatures and anomaly detection rules to identify potential exploitation patterns. 7. Conduct regular audits of Suricata configurations and ensure that security patches are applied promptly. 8. Educate network security teams about this vulnerability and the importance of monitoring Suricata health metrics.