Which virtualization method is known to pose a potential security risk if the physical server is not secured properly?

Containerization is known to pose a potential security risk if the physical server is not secured properly because it operates by sharing the host operating system kernel among all containers. This means that if one container is compromised, an attacker could potentially gain access to other containers running on the same host or even to the host itself. The isolation between containers is not as robust as that provided by hypervisors, making the underlying security of the physical server critical. If the host server has vulnerabilities or if security measures like access controls are inadequately configured, it can lead to data breaches or unauthorized access across containers.

In comparison, Type 1 Hypervisors run directly on the hardware and provide strong isolation between virtual machines, which makes them generally more secure. Type 2 Hypervisors run on top of a host operating system, similar to containers, but they encapsulate virtual machines which have complete operating systems, also providing a higher level of isolation compared to container-based solutions. Application Streaming delivers applications to client devices without the need for local installation, which has its own set of security considerations but does not directly relate to the shared kernel vulnerabilities present in a containerized environment.