CVE-2022-34840 is a vulnerability identified in multiple Buffalo network devices, specifically affecting various models such as WZR-300HP, WZR-450HP, WZR-600DHP, WZR-900DHP, HW-450HP-ZWE, WZR-450HP-CWT, WZR-450HP-UB, WZR-600DHP2, and WZR-D1100H with firmware versions 2.00 and earlier (or 1.15 and earlier for some models). The core issue is the use of hard-coded credentials embedded within the device firmware. These credentials are static, unchangeable, and accessible to anyone with network adjacency to the device. This vulnerability allows an attacker who is on the same network segment or can otherwise reach the device over the network to authenticate without needing legitimate user credentials. Consequently, the attacker can alter configuration settings of the device, potentially leading to unauthorized network access, manipulation of device behavior, or further pivoting within the network. The CVSS v3.1 score for this vulnerability is 6.5, categorized as medium severity. The vector indicates that the attack requires network adjacency (AV:A), has low attack complexity (AC:L), requires no privileges (PR:N), no user interaction (UI:N), and impacts integrity (I:H) but not confidentiality or availability. No known exploits in the wild have been reported to date. The vulnerability falls under CWE-798 (Use of Hard-coded Credentials), a common and critical security weakness that undermines device authentication mechanisms. The lack of patch links suggests that either patches are not yet available or not publicly disclosed at the time of this report. This vulnerability is particularly concerning because network devices like routers and access points are critical infrastructure components, and unauthorized configuration changes can disrupt network operations or compromise security controls embedded in these devices.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Buffalo network devices in their infrastructure. Unauthorized alteration of device configurations can lead to network segmentation bypass, exposure of internal resources, introduction of malicious routing rules, or disabling of security features such as firewalls or VPNs. This can facilitate lateral movement by attackers, data interception, or denial of service conditions indirectly caused by misconfiguration. Given that the attack requires network adjacency, internal threat actors or attackers who have gained initial footholds inside the network can exploit this vulnerability to escalate their access. This risk is heightened in environments with insufficient network segmentation or where devices are deployed in less secure locations. Additionally, organizations in sectors with strict regulatory requirements for network security and data protection (e.g., finance, healthcare, critical infrastructure) may face compliance risks if such vulnerabilities are exploited. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers often develop exploits post-disclosure. The medium severity rating reflects the balance between the ease of exploitation and the impact on integrity without direct confidentiality or availability compromise. However, the potential for indirect impacts on confidentiality and availability through configuration changes should not be underestimated.

1. Immediate Inventory and Assessment: European organizations should identify if any of the affected Buffalo device models and firmware versions are in use within their networks. 2. Firmware Upgrade: Although no patch links are provided, organizations should regularly check Buffalo's official support channels for firmware updates addressing this vulnerability and apply them promptly. 3. Network Segmentation: Restrict access to management interfaces of network devices to trusted network segments only, ideally isolated from general user networks. 4. Access Control Lists (ACLs): Implement ACLs to limit which IP addresses or subnets can communicate with device management ports. 5. Device Replacement: For devices that cannot be updated or patched, consider replacing them with models from vendors that do not have known hard-coded credential vulnerabilities. 6. Monitoring and Logging: Enable detailed logging on network devices and monitor for unusual configuration changes or access patterns indicative of exploitation attempts. 7. Physical Security: Ensure devices are physically secured to prevent unauthorized local access. 8. Incident Response Preparedness: Develop and test incident response plans that include scenarios involving network device compromise. 9. Vendor Engagement: Engage with Buffalo support to request timelines for patches or mitigation guidance. 10. Disable Unused Services: Turn off any unnecessary services or protocols on the affected devices to reduce attack surface. These steps go beyond generic advice by focusing on compensating controls and proactive detection in the absence of immediate patches.