What should be the first action to secure the web management interfaces of networked printers?

The first action to secure the web management interfaces of networked printers should be to change the default administrator password. Many networked devices, including printers, come with factory settings that include standard usernames and passwords. These default credentials are widely known and can be easily exploited by attackers, posing a significant security risk.

By changing the default password to a strong, unique password, you significantly reduce the risk of unauthorized access to the printer's management interface. This action is foundational because it prevents attackers from gaining control of the device in the first place. Once this step is taken, additional security measures, such as enabling encryption for communications or disabling remote access, can enhance security further. However, if the default credentials are not changed initially, those additional measures may be ineffective because an attacker could still gain access using the standard login credentials.

Focusing on the importance of the default password highlights the critical nature of addressing easily exploitable vulnerabilities as an initial step in securing networked devices.