Security Measures

Correct Answer: Implement WPA3 and use strong pre-shared keys

The best measure against unauthorized access to the company's wireless network is to 'Implement WPA3 and use strong pre-shared keys'. WiFi Protected Access 3 (WPA3) is the latest and most secure wireless network encryption method. The use of strong pre-shared keys (PSK) increases the difficulty for unauthorized devices to connect as it would require knowledge of the key. 'Conduct regular device audits' is a reactive measure and won't necessarily prevent unauthorized access in real-time. 'Disable the wireless network' is not practical in most business environments as it would disrupt operations. 'Limit the number of devices that can connect to the wireless network' would not ensure that all the devices are authorized, as unauthorized devices could potentially connect before authorized ones.

Correct Answer: Inspect the outgoing data from the network

Inspecting the outgoing data from the network is the most effective way of dealing with this problem. This allows the network administrator to monitor the traffic and identify any unusual patterns or unauthorized data transfers, which could indicate that an attacker is trying to steal company data. On the other hand, upgrading all the hardware, changing all user passwords, or implementing new antivirus software may not necessarily prevent data theft, especially if the attackers have already gained access to the network.

Correct Answer: Expired or invalid certificate

The most likely cause of the problem is an expired or invalid certificate. VPNs that use a certificate-based authentication method require a valid certificate to establish a secure connection. If the certificate is expired or invalid, the VPN connection will fail. As for the other options: A weak Internet connection could potentially cause issues with using the VPN, but this isn't directly tied to the VPN's authentication method. An employee's device being out of storage space wouldn't directly affect their ability to authenticate with the VPN. Lastly, while using an unsupported VPN client can cause connection issues, this again doesn't inherently tie to certificate-based authentication issues. Therefore, the most probable issue directly tied to certificate-based authentication would be an expired or invalid certificate.