Each client is unique and different

Each client is then part of the cloud’s shared infrastructure. Anything between the Internet and the servers is a shared embedded computer infrastructure. If something happens to the shared infrastructure, all customers hosted in the cloud will be affected. If a firewall goes down, nobody can access the cloud. About 63 percent of embedded computer attacks strike the shared infrastructure as it’s the first thing the attack will hit.“Prior to recent attacks on embedded computer financial institutions in the U.S., there was not much awareness or knowledge of embedded computer attacks and other cyber threats,” Kenig says.

refer to: http://mil-embedded.com/articles/cloud-security-the-dod/