Sep 01 2009

Audit of security control and scoping

Category: Risk Assessment,Security ComplianceDISC @ 3:53 pm


Information Technology Control and Audit

The audit is utilized as a tool to check compliance control based on standards such as ISO 27002 or NIST 800-53 etc. Some other terms which are not sometime rigorous audit have been used to asses controls are gap analysis, benchmarking and control review.

Scoping sets the boundaries of the audit, where dependencies are marked and exclusions are sorted out.

The consultant/team lead that has a thorough understanding of security risk management ought to carry out these reviews. The quality of the work depends on correct scoping, fieldwork assignment, and appropriately reporting the findings to management.

Team lead should have a clear understanding of audit scope before the initial briefing to client. Basically what exactly the client wants and who are the target audiences in the final report and presentation. Clear understanding of the scope includes making sure that the whole organization is included in the audit or just part of it. Before starting an audit, the auditor should have a complete list of assets included in the scope. Sort the assets list into different group of infrastructure which could be handed over to technical consultant for validation of the controls. At this point team lead should point out to technical consultant, the minimum number of assets which are required to be validated to satisfy sampling requirement.

Scope of final report/presentation should be clear regarding the list of non-compliance, prioritized recommendation or action plans which needs to be included in the report. During presentation of the findings, and to keep C level folks interested in the presentation, presenter needs to relate the findings to business risk and avoid using security acronym.

Scoping will take into account the length of the time available for field work, analysis, reporting and size and competence of the team to perform a successful audit. Especially if limited time is available for field work, the competence of the team matter to cover various infrastructure, to validate and document the controls effectively.

Tags: assessment profile, assessment scope, iso 27002, NIST 800-53, security audit, security control, security review, Security Risk Assessment

Aug 18 2009

Control selection and cost savings

Category: Security Risk AssessmentDISC @ 3:53 pm


Information Security Risk Analysis

In risk management, risk treatment process begins after completion of a comprehensive risk assessment.
Once risks have been assessed, risk manager utilize the following techniques to manage the risks

• Avoidance (eliminate)
• Reduction (mitigate)
• Transfer (outsource or insure)
• Retention (accept and budget)

Now the question is how to select an appropriate control to avoid or reduce risk. While selecting appropriate control to mitigate and avoid risk we need to consider compensating control to cut cost and supplemental control to increase protection for sensitive or classified assets.

Compensating control is a safeguard or countermeasure is employed by an organization in lieu of recommended security control from standards such as ISO 27002 or NIST 800-53. Compensating control provides an equivalent or comparable protection for information system to the original control requirement form standard. For example, even though most standards recommend separation of duties, but for a small operation it might be an unacceptable cost to separate the duties of system administration and system auditing. In that case system owner can utilize compensating control such as strengthening the audit and personnel security.

On the other hand with supplemental control, the system owner may decide to supplement the control to achieve more protection for sensitive and classified assets. If there is high likelihood or magnitude of impact is high should a threat exploit a given vulnerability you might want to consider a supplemental control because overall risk is high. For example you might want to utilize defense in depth method to safeguard your crown jewel.

Implementing and monitoring security control can be expensive, system owner are pressured by management to look for cost savings without any reduction in the security posture of an organization. The system owner can either inherit the common controls or segment the system exposure to reduce cost and risks.
Common controls are the security controls which have been implemented by another information system that your system can utilize. Basically working with another system owner who has utilized some of the security controls need to be implemented in your system. For example utilize the corporate office base line hardening configuration for Windows and Unix system instead of developing your own. This will significantly reduce the cost of developing, testing and maintaining a secure baseline configuration.

Best and cheapest method of cost reduction is to segment the information system into multiple systems which will add different layers and levels of security into each system. Basically you put your crown jewel in multiple layers of security if one control breaks there is another control in place to monitor and protect your assets. This will allow the system owner to focus implementing higher security controls to the segment with most sensitive or classified information instead of entire system

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Tags: common control, iso 27002, iso assessment, ISO audit, NIST 800-53, NIST audit, risk analysis, Risk Assessment, Risk management

Aug 10 2009

Managing Risks and NIST 800-53

Category: Security Risk AssessmentDISC @ 5:48 pm

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FISMA Certification & Accreditation Handbook

The organizations need to establish security program to manage their day to day risks. Before selecting the controls from standards such as (NIST 800-53 or ISO 27002), organizations need to have complete inventory of the assets involved in the scope. Assets involved in the scope would require a comprehensive risk assessment to determine the sensitivity/criticality of these assets. Depending on the categorization of these assets will determine an appropriate control from standard to mitigate relevant risk. In some cases supplemental controls may be required.

Management of risks involves the risks to the organization with the operation of an information system or information security management system. Risk management is an effective frame work for selecting appropriate security controls for an information system and assist in selecting of appropriate security controls to protect assets.

Both ISO and NIST standards follow the similar path in control selections. NIST 800-53 has 163 high level controls and 154 medium level controls which have around 95% mapping with ISO 27002 which has 133 controls. While NIST SP 800-53 is required for federal (unclassified) information system, NIST encourages its use in commercial space. Commercial organizations can utilize the NIST standard to create their security program, which will provide a road map to their security strategy and assist in making informed decisions for securing their information assets.

The management of day to day risks is a key element in an organization’s information security program and both NIST and ISO provide an effective framework for selecting and managing the appropriate security controls for information system. ISO utilize PDCA (Plan, Do Check, and Act) Deming model for selecting the appropriate security controls and managing its information security management system. NIST on the other hand utilize the similar framework for selecting and managing appropriate controls for information system and is called risk management framework security life cycle. Copy of the NIST risk management framework security life cycle is available to see an eerie resemblance with PDCA model.


Around 80% of critical infrastructure resides in private sectors which required to be protected by various regulations. Both NIST and ISO can be utilized to protect assets, however in some cases one standard might fit better in your environment then the other or perhaps you are able to manage one standard better then the other. Both standards required their information system to be audited or reviewed by authorized organizations to achieve apporpriate certifications.

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Tags: iso 27001, iso 27002, NIST 800-53, PDCA, Risk management