| Layer |
Sharing this layer uses... |
Examples |
Security Implications |
| Application |
Software as a Services (SaaS): your users
access software directly from provider. |
Facebook, Google Docs |
You're relying entirely on the provider's
security, including account authentication & reset
procedure. |
| Code Runtime Environment |
Platform as a Service (PaaS): your code runs
on top of provider's Python, PHP, Java, or Node.js
development environment. |
Google
App Engine, AWS Lambda |
API keys tend to leak, and can allow much
more access than you intend. SQL or JS injection is still a problem. |
| OS Kernel |
Containers: combine application and runtime
libraries into a single portable image, run on shared
kernel. |
Docker, rkt, Microsoft Azure |
Kernel-level vulnerabilities are accessible
to any containerized application. |
| Server box |
Infrastructure as a Service (IaaS): virtual
machines use a hypervisor to mediate your access to
provider's hardware. |
Amazon EC2, Digital Ocean, Rackspace |
An attacker might be sharing your CPU
(including branch history table and L1 cache), your RAM, and
your network connection, making very fine-grained timing
attacks possible. Virtual server sprawl plus the need to patch VMs individually means some VMs may be running old vulnerable kernels. |
| Datacenter |
Colocation (colo): rent rack space in your
ISP's datacenter for your server hardware. |
GCI,
ACS |
Everything about your server's security
(patching, configuration, firewalls) is up to you. An attacker can gain physical access to colo hardware by just renting space. (Countermeasure: locking cabinets, video recording.) |