Firmware is the software built into a device such as a camera, recorder or controller, and firmware security is the practice of keeping it current, authentic and unreachable from untrusted networks. Unpatched firmware is one of the most common ways a camera becomes a foothold on a network.
A camera can run for years without anyone logging into it. That quiet life is convenient for the site and useful for an attacker, because the firmware may not have changed since installation.
Why firmware matters
Firmware handles the network stack, the web interface and often the recording logic. A known flaw in any of them can be used without a password. Because devices are numerous and rarely visited, one missed update can leave a whole camera network exposed.
Updating without breaking a system
Read the release notes, test on one device and keep a copy of the working version. Update recorders and their cameras together where the vendor requires matched versions. Retire devices that no longer receive updates, and put them behind a restricted network in the meantime. Keep a record of each device’s version, so a gap is visible.