Earlier this week we had a team of folks at the Gartner Security Event in Washington DC. A visitor to our booth from a large Secure Web Gateway vendor questioned the need for a Cloud Access Security Broker (CASB). "Who uses unmanaged devices?" he asked. "A gateway proxy at the firewall is just fine, and company owned laptops are configured to proxy through no matter where they are."
Hmm....indeed there are CASBs built around ancient forward proxy technology that only works on managed devices configured to point to them. But in a world of 2B unmanaged mobile devices, these are anachrostic antiques. And to state the obvious, most hackers use unmanaged devices.
Hackers who steal your data can be in another country and are not waiting to steal your laptop at the local Starbucks first. And they use unmanaged devices.
So if your security technology only protects data on managed devices, it is long obsolete.