CVE-2024-45796 is a medium severity vulnerability classified as CWE-193 (Off-by-one Error) found in the Suricata network security monitoring engine prior to version 7.0.7. Suricata is widely used as an Intrusion Detection System (IDS), Intrusion Prevention System (IPS), and Network Security Monitoring (NSM) tool. The vulnerability arises from a logic error in the fragment reassembly process, where an off-by-one mistake causes Suricata to fail reassembling certain valid fragmented packets correctly. An attacker can exploit this by crafting network packets with specific fragmentation patterns that trigger the faulty logic, causing Suricata to drop or mishandle these fragments. This leads to incomplete or failed reassembly of network traffic, which in turn can cause Suricata to miss malicious payloads embedded within fragmented packets. The flaw does not allow direct compromise of the system or denial of service but undermines the integrity of Suricata’s detection capabilities, potentially allowing attackers to evade detection. Exploitation requires no privileges or user interaction and can be performed remotely over the network. The issue was publicly disclosed on October 16, 2024, and fixed in Suricata version 7.0.7. No known exploits are currently reported in the wild. The CVSS v3.1 base score is 5.3, reflecting a network attack vector with low complexity and no privileges required, but limited impact confined to detection integrity without affecting confidentiality or availability.

For European organizations, this vulnerability poses a risk primarily to the integrity of network security monitoring and intrusion detection processes. Suricata’s failure to properly reassemble fragmented packets can allow attackers to bypass detection mechanisms, potentially enabling stealthy network attacks or data exfiltration attempts to go unnoticed. This can be particularly critical for sectors relying heavily on Suricata for real-time threat detection, such as financial services, telecommunications, energy, and government agencies. While the vulnerability does not directly compromise system availability or confidentiality, the reduced detection fidelity increases the risk of undetected intrusions and prolonged attacker presence. Organizations with high network traffic volumes and complex fragmentation scenarios may experience more pronounced impacts. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially given the ease of exploitation and remote attack vector. Failure to patch could undermine compliance with European cybersecurity regulations that mandate effective intrusion detection capabilities.

The primary mitigation is to upgrade Suricata to version 7.0.7 or later, where the off-by-one error in fragment reassembly is corrected. Organizations should prioritize patching Suricata deployments, especially those monitoring critical network segments. In addition, network administrators should implement monitoring and alerting for unusual fragmentation patterns that could indicate exploitation attempts. Deploying complementary IDS/IPS solutions or network traffic analysis tools can provide defense-in-depth to detect evasion attempts. Regularly reviewing Suricata logs for dropped or malformed fragments and correlating with other security events can help identify suspicious activity. Network segmentation and limiting exposure of Suricata sensors to untrusted networks reduce attack surface. Finally, maintaining an up-to-date asset inventory and vulnerability management process ensures timely identification and remediation of vulnerable Suricata instances.