CVE-2024-52616 identifies a vulnerability in the Avahi-daemon, a widely used open-source implementation of multicast DNS (mDNS) and DNS Service Discovery (DNS-SD) protocols. The flaw arises because the daemon initializes DNS transaction IDs with a random value only once during startup, after which it increments these IDs sequentially for subsequent DNS queries. This predictable sequence drastically reduces the entropy of transaction IDs, which are intended to be random to prevent spoofing. DNS transaction IDs are critical for matching DNS responses to requests; predictable IDs allow an attacker to craft spoofed DNS responses that appear legitimate. This can enable DNS spoofing attacks, where an attacker intercepts or redirects network traffic by responding with forged DNS answers. The vulnerability does not affect confidentiality or availability directly but compromises the integrity of DNS responses, potentially redirecting users to malicious sites or enabling man-in-the-middle attacks. The CVSS v3.1 base score is 5.3 (medium), reflecting network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to integrity. No patches or exploits are currently documented, but the flaw is significant for environments relying on Avahi for local network service discovery. The vulnerability was published on November 21, 2024, with Red Hat as the assigner. The flaw is particularly relevant for Linux-based systems and IoT devices using Avahi for zero-configuration networking.

For European organizations, the primary impact of CVE-2024-52616 lies in the potential compromise of DNS integrity within local networks using Avahi-daemon. This can lead to DNS spoofing attacks that redirect users or services to malicious endpoints, enabling phishing, credential theft, or lateral movement within corporate networks. Organizations relying on Avahi for service discovery in critical infrastructure, industrial control systems, or IoT deployments may face increased risk of targeted attacks. Although confidentiality and availability are not directly affected, the integrity breach can undermine trust in network communications and facilitate further exploitation. The medium severity rating indicates a moderate risk that should not be ignored, especially in sectors with stringent security requirements such as finance, healthcare, and government. The lack of required privileges or user interaction lowers the barrier for attackers, increasing the likelihood of exploitation in poorly segmented or monitored networks. European organizations with extensive Linux deployments or those using Avahi in mixed OS environments should prioritize assessment and mitigation to prevent DNS spoofing-based attacks.

1. Update Avahi-daemon to the latest version where the transaction ID generation is properly randomized per DNS query, eliminating predictable sequences. 2. If immediate patching is not possible, implement network-level protections such as DNSSEC within local networks to validate DNS responses and prevent spoofing. 3. Employ network segmentation and strict firewall rules to limit exposure of mDNS/DNS-SD traffic to trusted devices only. 4. Monitor network traffic for anomalous DNS responses or unexpected transaction ID patterns indicative of spoofing attempts. 5. Use intrusion detection/prevention systems (IDS/IPS) configured to detect DNS spoofing signatures. 6. Educate network administrators about the risks of predictable DNS transaction IDs and encourage regular software updates. 7. Consider disabling Avahi or mDNS services on systems where they are not required to reduce attack surface. 8. For IoT and embedded devices using Avahi, coordinate with vendors for firmware updates or mitigations. 9. Conduct penetration testing and vulnerability assessments focusing on DNS spoofing vectors in local networks. 10. Maintain an inventory of systems running Avahi to prioritize remediation efforts effectively.