A cloud security service is made available to endpoint computers. Network traffic from originating application programs running on endpoint computers are redirected to the cloud security service based on characteristics of the originating application programs. Network traffic from an originating application program may be redirected to the cloud security service by way of a virtual private network (VPN) tunnel or generic routing encapsulation (GRE) tunnel between an endpoint computer and a cloud computing system hosting the cloud security service, for example. Network traffic from an originating application program may also be routed from an endpoint computer to a gateway system, and then redirected from the gateway system to the cloud computing system. The cloud security service may drop or forward network packets of the network traffic depending on a result of scanning the network packets.