Simple Custom Detection is a feature of Cisco AMP for Endpoints that allows administrators to block specific files based on their SHA-256 or MD5 hashes. This feature can be used to detect and quarantine files of unknown disposition, such as abc424400664.zip, by adding their hashes to a custom list in the AMP portal. The list can then be applied to a policy that is assigned to the endpoints. Simple Custom Detection works on files of any type, size, or platform, unlike the other options that are either platform-specific (Android Custom Detection), size-limited (Blocked Application), or signature-based (Advanced Custom Detection). References: 1, 2, 3