CVE-2024-23690 is an OS command injection vulnerability classified under CWE-78, found in the Telnet interface of Netgear FVS336Gv2 and FVS336Gv3 routers, which are now end-of-life products. The vulnerability arises from improper neutralization of special elements in the 'util backup_configuration' command, allowing an authenticated remote attacker to inject arbitrary OS commands executed with root privileges. The attack vector is network-based (AV:N), requires low attack complexity (AC:L), but does require high-level privileges (PR:H) and no user interaction (UI:N). The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). Exploitation involves connecting to the device's Telnet service and sending crafted commands to execute arbitrary shell commands, potentially leading to full device compromise, data exfiltration, or disruption of network services. No public exploits or patches are currently available, increasing the risk for organizations continuing to use these devices. The vulnerability is particularly critical because the devices are often used as VPN gateways or firewalls in small to medium business environments, making them attractive targets for attackers seeking network footholds. The lack of patch availability and the end-of-life status of the devices complicate remediation efforts.

For European organizations, this vulnerability poses a significant risk to network security, especially for those still operating legacy Netgear FVS336Gv2 or FVS336Gv3 routers. Successful exploitation can lead to complete device takeover, allowing attackers to intercept, modify, or disrupt network traffic, potentially compromising sensitive data and internal systems. The high impact on confidentiality, integrity, and availability could disrupt business operations, cause data breaches, or enable lateral movement within corporate networks. Critical sectors such as finance, healthcare, and government agencies using these devices for VPN or firewall functions are particularly vulnerable. The absence of patches means organizations must rely on network-level mitigations or device replacement, increasing operational costs and complexity. The requirement for authentication limits the attack surface but does not eliminate risk, as credential compromise or insider threats could facilitate exploitation. Additionally, the use of Telnet, an insecure protocol, exacerbates the risk of credential interception and unauthorized access.

1. Immediately disable Telnet access on all Netgear FVS336Gv2 and FVS336Gv3 devices to eliminate the remote attack vector. 2. Restrict administrative access to these devices to trusted management networks using firewall rules or VPNs. 3. Replace affected devices with currently supported and patched models to ensure ongoing security updates. 4. Implement strong authentication mechanisms and regularly rotate credentials to reduce the risk of credential compromise. 5. Monitor network traffic for unusual Telnet connections or command patterns indicative of exploitation attempts. 6. If device replacement is not immediately feasible, isolate the devices from critical network segments to limit potential impact. 7. Educate network administrators about the risks of using end-of-life devices and insecure protocols like Telnet. 8. Consider deploying network intrusion detection systems (NIDS) with signatures to detect exploitation attempts targeting this vulnerability. 9. Maintain an inventory of all network devices to identify and prioritize remediation of vulnerable hardware. 10. Engage with Netgear support or authorized vendors for any potential firmware updates or workarounds, despite the end-of-life status.