Application filter objects are used by Firepower devices. An application filter object defines the applications used in an IP connection, or a filter that defines applications by type, category, tag, risk, or business relevance. You can use these objects in policies to control traffic instead of using port specifications.
Although you can specify individual applications, application filters simplify policy creation and administration. For example, you could create an access control rule that identifies and blocks all high risk, low business relevance applications. If a user attempts to use one of those applications, the session is blocked.
You can select applications and application filters directly in a policy without using application filter objects. However, an object is convenient if you want to create several policies for the same group of applications or filters. The system includes several pre-defined application filters, which you cannot edit or delete.
Note: Cisco frequently updates and adds additional application detectors via system and vulnerability database (VDB) updates. Thus, a rule blocking high risk applications can automatically apply to new applications without you having to update the rule manually.
Note: When an FDM managed FTD device is onboarded to CDO, it converts the application filters to application filter objects without altering the rule defined in Access Rule or SSL Decryption. Because of a configuration change, the device's configuration status is changed to 'Not Synced' and requires configuration deployment from CDO. In general, FDM does not convert the application filters to application filter objects until you manually save the filters.