A recently discovered vulnerability, CVE-2024-2182, affects the Open Virtual Network (OVN) clusters, specifically ones utilizing Bidirectional Forwarding Detection (BFD) for high availability between hypervisors. This vulnerability allows attackers to inject carefully crafted BFD packets from within unprivileged workloads, which can lead to a denial of service. In this post, we will dive into the details of the vulnerability, including information about OVN, BFD, and the associated risks.

What is Open Virtual Network (OVN)?
OVN (Open Virtual Network) is a system for supporting virtual networks in an OpenStack or other virtualized environment. It provides network virtualization capabilities, allowing for the creation and management of multiple isolated virtual networks on a single physical network. More information about OVN can be found on its official website: https://www.ovn.org/

What is Bidirectional Forwarding Detection (BFD)?
BFD (Bidirectional Forwarding Detection) is a protocol designed to detect failures in communication paths and provide rapid notification to other participating nodes. This is particularly crucial in scenarios where high availability is a requirement. BFD allows hypervisors to quickly detect and initiate the recovery process in case of a failure, maintaining service availability for end users. To learn more about BFD, visit the following link: https://www.rfc-editor.org/rfc/rfc588.txt

Exploit Details

The vulnerability, CVE-2024-2182, specifically affects OVN clusters that utilize BFD between hypervisors for high availability. An attacker can exploit this flaw by injecting specially crafted BFD packets from inside unprivileged workloads, such as virtual machines or containers. Doing so can trigger a denial of service in the affected OVN clusters.

Here is a code snippet showing what an attacker might do to exploit this vulnerability

import socket
import sys

# Craft the malicious BFD packet
def create_bfd_packet():
    # Insert malicious packet content here
    pass

# Send the malicious BFD packet over the network
def send_bfd_packet(packet):
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.sendto(packet, ('<target_IP>', <target_port>))
        sock.close()
    except socket.error as e:
        print("Error sending packet:", e)
        sys.exit(1)

if __name__ == "__main__":
    malicious_packet = create_bfd_packet()
    send_bfd_packet(malicious_packet)

To be clear, this code is provided for educational purposes only. It is important to understand how such an attack can occur to better protect against it and to ensure that security professionals can effectively respond and mitigate the vulnerability.

References

Here are some important links you can visit to keep up-to-date with the development of this vulnerability:

1. OVN official website: https://www.ovn.org/
2. BFD protocol description: https://www.rfc-editor.org/rfc/rfc588.txt
3. CVE-2024-2182 official record: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-2182

Mitigation and Conclusion

It is highly recommended to upgrade your OVN infrastructure's software to the latest available version to ensure the security of your environment. In particular, the OVN community should release a patch to address this vulnerability soon, so be sure to keep an eye out for updates.

In conclusion, the CVE-2024-2182 vulnerability is a serious flaw that affects OVN clusters utilizing BFD for high availability. By understanding both the details and risks associated with this vulnerability, organizations can take the appropriate steps to ensure the security and high availability of their OVN infrastructure.

Timeline

Published on: 03/12/2024 17:15:59 UTC
Last modified on: 03/23/2024 03:15:12 UTC