In multi-tenant environments, Linux containers managed by Docker or Kubernetes have a lower resource footprint, faster startup times, and higher I/O performance com- pared to virtual machines (VMs) on hypervisors. Yet their weaker isolation guarantees, enforced through soft- ware kernel mechanisms, make it easier for attackers to compromise the confidentiality and integrity of applica- tion data within containers.
We describe SCONE, a secure container mechanism for Docker that uses the SGX trusted execution support of Intel CPUs to protect container processes from out- side attacks. The design of SCONE leads to (i) a small trusted computing base (TCB) and (ii) a low performance overhead: SCONE offers a secure C standard library in- terface that transparently encrypts/decrypts I/O data; to reduce the performance impact of thread synchronization and system calls within SGX enclaves, SCONE supports user-level threading and asynchronous system calls. Our evaluation shows that it protects unmodified applications with SGX, achieving 0.6✓–1.2✓ of native throughput.