Suricata is an open-source network Intrusion Detection System (IDS), Intrusion Prevention System (IPS), and Network Security Monitoring (NSM) engine widely deployed for monitoring network traffic and detecting malicious activity. CVE-2024-47522 is a vulnerability identified in Suricata versions before 7.0.7, involving a reachable assertion failure (CWE-617) triggered by processing invalid Application-Layer Protocol Negotiation (ALPN) fields within TLS or QUIC traffic. This vulnerability manifests when JA4 matching and logging features are enabled, which are used for JA3/JA4 fingerprinting of TLS/QUIC handshakes to identify client and server applications. When Suricata encounters malformed ALPN data under these conditions, it triggers an assertion failure that causes the Suricata process to abort unexpectedly, resulting in a denial of service (DoS). The vulnerability does not affect confidentiality or integrity but severely impacts availability by crashing the monitoring engine. Exploitation requires no authentication or user interaction and can be triggered remotely by sending crafted TLS/QUIC traffic with invalid ALPN values. The issue has been addressed in Suricata version 7.0.7, which corrects the assertion handling. As a temporary workaround, disabling JA4 matching and logging prevents the assertion from being triggered. This vulnerability is tracked under CVE-2024-47522 with a CVSS v3.1 score of 7.5, reflecting its high severity due to network attack vector, low complexity, no privileges required, and high impact on availability.

The primary impact of CVE-2024-47522 is a denial of service condition affecting Suricata deployments that have JA4 matching enabled. Suricata is often deployed in critical network security environments including enterprise networks, government agencies, and service providers. An attacker can remotely cause Suricata to crash by sending malformed TLS or QUIC traffic with invalid ALPN fields, disrupting network monitoring and intrusion detection capabilities. This loss of visibility can delay detection of other attacks, reduce incident response effectiveness, and potentially allow malicious activity to go unnoticed. Organizations relying heavily on Suricata for real-time threat detection and prevention may experience operational disruptions and increased risk exposure. Although no known exploits are reported in the wild, the ease of triggering the assertion failure means attackers with network access could exploit this vulnerability. The impact is limited to availability; confidentiality and integrity of monitored traffic are not directly affected. However, the resulting monitoring blind spots can indirectly increase overall security risk.

1. Upgrade Suricata to version 7.0.7 or later immediately, as this version contains the fix for the assertion failure vulnerability. 2. If immediate upgrade is not feasible, disable JA4 matching and logging in Suricata configuration to prevent the assertion from being triggered by malformed ALPN fields. 3. Monitor network traffic for unusual TLS/QUIC handshake anomalies that could indicate attempts to exploit this vulnerability. 4. Implement network segmentation and filtering to limit exposure of Suricata sensors to untrusted or external networks where malicious traffic could originate. 5. Regularly review Suricata logs and alerts for unexpected crashes or restarts that may indicate exploitation attempts. 6. Incorporate this vulnerability into incident response playbooks to quickly identify and remediate potential denial of service events related to Suricata. 7. Engage with Suricata community and vendor advisories for any additional patches or mitigations. 8. Consider deploying redundant Suricata sensors or failover mechanisms to maintain monitoring continuity in case of crashes.