CVE-2024-23837 is a vulnerability classified under CWE-770, which concerns allocation of resources without limits or throttling. The affected component, libhtp, is a security-aware HTTP protocol parser widely used in network security tools developed by the Open Information Security Foundation (OISF), such as Suricata. The vulnerability arises when libhtp processes specially crafted HTTP headers that cause it to consume excessive CPU resources due to unbounded allocation or processing loops. This leads to a denial of service condition by exhausting processing capacity, effectively disrupting the availability of services relying on libhtp for HTTP parsing. The flaw does not impact confidentiality or integrity but severely affects availability. Exploitation requires no privileges or user interaction and can be triggered remotely by sending malicious HTTP traffic. The issue was addressed in libhtp version 0.5.46, which introduced limits or throttling mechanisms to prevent excessive resource consumption during header parsing. No public exploits have been reported yet, but the vulnerability’s characteristics make it a credible DoS vector against network security devices or applications using vulnerable libhtp versions.

For European organizations, this vulnerability poses a significant risk to the availability of network security infrastructure and applications that rely on libhtp for HTTP parsing. Denial of service attacks exploiting this flaw could disrupt intrusion detection and prevention systems (e.g., Suricata), web application firewalls, or other security appliances, potentially leading to downtime or degraded security monitoring capabilities. Critical sectors such as finance, telecommunications, government, and critical infrastructure operators in Europe could face operational interruptions and increased exposure to other threats during service outages. The lack of confidentiality or integrity impact limits the risk to data breaches, but the availability impact alone can have severe business continuity consequences. Organizations with high traffic volumes or exposure to untrusted HTTP traffic are particularly vulnerable to exploitation attempts.

The primary mitigation is to upgrade libhtp to version 0.5.46 or later, where the vulnerability is fixed. Organizations should audit their environments to identify all instances of libhtp usage, including embedded systems and security tools like Suricata. In addition to patching, deploying network-level rate limiting and anomaly detection to identify and block suspicious HTTP header patterns can reduce the risk of exploitation. Implementing resource usage monitoring on affected systems can help detect early signs of exploitation attempts. Security teams should also review firewall and intrusion detection rules to detect abnormal HTTP traffic patterns indicative of this attack. Regular vulnerability scanning and timely patch management processes are essential to prevent exploitation. Finally, organizations should stay informed about any emerging exploits or proof-of-concept code related to this vulnerability.