Information Security Policies
Information security policies, whether corporate policies, business unit policies, or regional entity policies provide the requirements for the protection of information assets. An information security policy is often based on the guidance provided by a frame work standard, such as ISO 17799/27001 or the National Institutes of Standards and Technology's (NIST) Special Publication (SP) 800 series standards. The Standards are effective in providing requirements for the "what" of protection, the measures to be used, the "who " and "when" requirements tend to be organization-specific and are assembled and agreed based on the stakeholders' needs.
Governance, the rules for governing an enterprise are addressed by security-relevant roles and responsibilities defined within the policy. Decision making is a key governance activity performed by individuals acting in roles based on delegated authority for making the decision and oversight to verify the decision was properly made and appropriately implemented. Aside from requirements for protection measures, policies carry a variety of basic concepts throughout the entire document. Accountability, isolation, deterrence, assurance, least privilege and separation of duties, prior granted access, and trust relationships are all concepts with broad application that should be consistently and appropriately applied.
Policies should ensure compliance with applicable statutory, regulatory, and contractual requirements. Auditors and corporate counsel often provide assistance to assure compliance with all requirements. Requirements to resolve stakeholder concerns may be formally or informally presented. Needs for the integrity of systems and services, the availability of assets when needed, and the confidentiality of sensitive information can vary significantly based on cultural norms and the perceptions of the stakeholders.
The criticality of the business processes supported by specific assets presents protection issues that must be recognized and resolved. Risk management requirements for the protection of especially valuable assets or assets at special risk also present important challenges. NIST advocates the categorization of assets for criticality, while asset classification for confidentiality is a long standing best practice.
Requirements for policy may arise from a contractual source or from a partner's request, the Payment Card Industry's Data Security Standard (PCI DSS) requires a policy addressing the Standard's requirements that applies to all assets within the scope of the standard. DSS requirements can be integrated into a single corporate policy but given the stringency of the requirements an enterprise may elect to segregate protection domains with separate dedicated policies so that less stringent requirements are applied to assets outside the scope of the DSS, saving resources and tailoring protection based on the lesser perceived threat/risk to the assets.
Risk assessments are an important source of policy requirements that are specific to the environment and assets to be protected. Risk mitigation measures based on an assessment of risk and the assets at risk allows managers the opportunity to weigh investment against potential damage to reach a level of risk acceptable to the decision makers.
Attacks targeting online applications and their data have become an issue of well-founded concern, policy should focus on risks in this area by specifically addressing the software development lifecycle and measures to ensure bespoke applications are sufficiently robust to withstand common attacks.
Policies should be reviewed and accepted at senior levels, ensuring the policy's authorizing authority has the stature necessary to make policy compliance mandatory. An authorization process to document and approve instances of noncompliance should also be provided. Often a compliance window is granted to allow time for the implementation of the policy by all applicable organizational entities.
Auditors often provide assurance of compliance as a result of their activities. The senior Auditor is also an important stakeholder and reviewer of policy drafts and amendments. Policies should be reviewed on an agreed schedule, often every two or three years. Changes in technology, evolution of business objectives and changes to the organization's goals and processes all act to invalidate and outdate a policy. Keeping the policy fresh and relevant is essential to providing appropriate protection to important assets and supporting mission performance.
ISO 17799/27001 and NIST SP800-53A Revision3 both provide a long list of information protection best practices. There is frequently an inclination to declare one of the documents to be the corporate standard and demand policy comply with the corporate standard. Ignoring cost issues, there are several important things wrong with this approach, first and most importantly, it ignores risk realities. Best practices are the average, where extraordinary risks exist, they are too weak and where risk is significantly below average they are too strong, wasting resources. Policy should be based on reality, not an idealized set of homogenized requirements. Arguably the correct approach is to begin with a standard and bend it to fit the shape of the enterprise. There is one exception to this rule, shops that run an absolutely standard architecture can benefit from the simplicity and straightforward nature of a standardized policy. Governance issues remain and should be dealt with quickly and cleanly as exceptions.
Security guidelines, component configuration standards, and standard operating procedures are based on and build on the information security policy. Care should be exercised that the documents are consistent with each other and are reviewed and exercised for correctness and reliability. Security training is often based on the detailed documents ultimately leading to repeatable processes and a predictable level of protection being realized.
An information security policy is a necessary first step in securing an environment and providing appropriate protection to all information assets. Building consensus around a policy is an effective approach to resolving concerns and resistance to the idea of mandated controls. Listening to and involving stakeholders while ensuring the policy reflects their issues will go a long way in gaining acceptance of the program of protection.
