Securing Infrastructure

Security as an enterprise capability is covered in Governance, Risk, Security, and Compliance, as a form of applied risk management involving concepts of controls and assurance. But, securing infrastructure and applications must be a focus from the earliest stages of the digital product.

This document recognizes the concept of securing infrastructure as critical to the practice of digital delivery:

  • Physical security

  • Networking issues

  • Core OS

  • Cloud issues


Infrastructure security, whether for on-premises computing or for cloud services, is first and foremost a security architecture issue. Many existing security control frameworks are available that describe various categories of controls which can be used to secure infrastructure. These include ISO/IEC 27002:2013, NIST 800-53, Security Services Control Catalog (jointly developed by The Open Group and The SABSA Institute), and the Center for Internet Security Controls Version 7. These are comprehensive sets of security controls spanning many domains of security. While these control frameworks predate cloud computing, most of the control categories affecting infrastructure security apply in cloud services as well. In addition, security practitioners tasked with securing infrastructure may benefit from reference security architectures such as the Open Enterprise Security Architecture (O-ESA): A Framework and Template for Policy-Driven Security [G112] from The Open Group, which describes basic approaches to securing enterprise networks, including infrastructure.

Security Hierarchy[1] depicts some broad categories of security control types:

Security Hierarchy
Figure 1. Security Hierarchy

Common Security Practices

Since the advent of cloud computing, securing cloud infrastructure has been a key concern. Most of the security issues that exist in non-cloud environments exist in cloud services as well. In other words, access control, user authentication, vulnerability management, patching, securing network access, anti-malware capabilities, data loss prevention, encryption of data, and a host of other security controls that we deploy in on-premises computing require careful consideration in cloud services. The security concerns around cloud computing vary depending on whether the cloud service is SaaS, PaaS, or IaaS.

On Premise versus Cloud Security Practices

There are also fundamental differences in security controls deployed in on-premises infrastructure (security controls may be physical or virtual), and those deployed in cloud infrastructure (which is purely virtual). These differences follow on from the shift brought by cloud computing. In on-premises computing, security architects and security solution providers had access to the physical computing networks, so physical security devices could be deployed in-line. The most common security design patterns leverage this physical access. In cloud services, there is no ability to insert security components which are physically in-line. This means that in cloud computing, we may have to utilize virtual security appliances, and virtual network segmentation solutions such as Virtual Local Area Networks (VLANs) and Software-Defined Networks (SDNs) versus physical security approaches.

Another difference in securing physical versus cloud infrastructure arises in defining and implementing microsegmentation (small zones of access control). In physical networks, multiple hardware firewalls are required to achieve this. In cloud computing, VLANs and SDNs may be used to deliver equivalent capability, with some unique advantages (they are more manageable, at a lower capital expense).

In addition, the responsibility for securing cloud infrastructure varies considerably based upon the service model as well. While early focus on cloud security tended to focus on potential security concerns and gaps in security capabilities, the security community today generally acknowledges that while security concerns relating to cloud computing persist, there is also an opportunity for cloud services to “raise the bar”, improving upon baseline security for many customer organizations. Hybrid cloud computing combining public cloud services with private cloud infrastructure brings further complexity to infrastructure security.

Evidence of Notability

The need to secure computing infrastructure has been obvious and self-evident for decades, and has evolved alongside changes in popular computing paradigms, including the mainframe era, client/server computing, and now cloud computing. The need for specific, unique guidance relating to securing cloud services of various types emerged in 2009, when the Cloud Security Alliance (CSA) was first formed, and when they published Version 1 of their Security Guidance for Critical Areas of Focus in Cloud Computing. The CSA guidance is now on Version 4, and includes 14 different security domains.


Organizations accustomed to deploying physical security capabilities on their own infrastructure may find it difficult to adapt to the challenges of securing cloud infrastructure in the various types cloud services. They may also have challenges adapting to the changes in responsibilities that are brought by the use of cloud services, where the Cloud Service Provider (CSP) is responsible for delivering many security capabilities, especially in SaaS services, and as a result the customer organization needs to specify needed security capabilities in Request for Proposals (RFPs). In addition, incident response management routines will require change.

Related Topics