Assume Breach
Definition
This means that you are always prepared with preparations that ensure that if someone were to gain unapproved access to your network, application, data, or other systems you would be able to respond. In cases where a production security bug is brought to the attention of your staff you will assume that it is currently being used by an attacker and use your preparation to hunt down any traces of it. To do this it will require extensive monitoring and logging to be set up in order to audit your systems if/when any issues do occur.