The Enemy Within: Firewalls and Backdoors
As a modern IT professional you've done all the right things to keep the "bad guys" out: you protected your network with firewalls and/or proxies, deployed anti-virus software across all platforms, and secured your mobile workstations with personal firewalls. You may even be in the process of designing and deploying an enterprise-wide network and host intrusion detection framework to help keep an even closer eye on what's going on. Even with all this, are you really safe? Can your multiple-lines of defense truly protect your network from modern methods of intrusion?
This article presents an overview of modern backdoor techniques, discusses how they can be used to bypass the security infrastructure that exists in most network deployments and issues a wake-up call for those relying on current technologies to safeguard their systems/networks.

RedFang
Redfang is a small proof-of-concept application that finds non-discovereable Bluetooth devices by brute forcing the last six bytes of the device's Bluetooth address and doing a read_remote_name().