Custom applications and threats
Every once in a while, an application may not be known. This could be due to it being a new application that has not been used much in the wild or could be something a developer created in-house for which it is not reasonable to expect there to be signatures to identify the session. In these cases, it is possible to create custom applications that use custom signatures and can trigger an App-ID to positively identify the previously unknown application.
The need for a custom application usually starts with the discovery of an abnormality in the traffic log. In the following screenshot, I have discovered my solar power converter, and an IoT device is communicating with its home server over an unknown-tcp connection:
Figure 10.12 – An unknown-tcp application in the traffic log
There are two ways to address this issue:
- Implement an application override that forcibly sets all these sessions to a specific application...
