ZigBee is more popular than other wireless technologies for low-power sensor networks due to its small memory footprint and energy efficiency. However, its security is weaker, as it offers no protection against replay attacks where an attacker resends recorded packets. KillerBee is a tool that exposes vulnerabilities in ZigBee security through sniffing devices, replaying data streams, and cracking stored encryption keys, which can enable attacks like remotely unlocking a locked door. While the required hardware is relatively inexpensive, overwriting device firmware requires additional debugging equipment.