Use ISO 17799 to Improve Security and Minimize Risks

Fazila Nurani asked:

Most organizations are dependent upon their information and business systems, leaving them exposed to critical loss in the aftermath of a security breach. Fortunately, by implementing an information security management system (“ISMS”), as outlined in the only internationally accepted standard/code to address information security, a business can significantly reduce the risk of a security breach.

ISO/IEC 17799:2005 (“ISO 17799”), known as the Code of practice for information security management, was developed by an IT Security Subcommittee of the International Organization for Standardization and was published in June 2005. ISO 17799 is superior to other security standards because it is globally accepted and comprehensive. ISO 17799 has been cleverly crafted to work well across industries and geographies. Also, the International Organization for Standardization has consciously made this standard consistent with most other existing information security audit and control standards, such as those developed by the NIST (National Institute of Standards and Technology). Therefore, ISO 17799 can be the common framework that links to all other standards, regulatory requirements and corporate governance initiatives.

ISO 17799 provides practical guidelines for developing organizational security controls and effective security management practices. An ISO 17799 evaluation results in a snapshot of the company’s security infrastructure, in that it provides a high-level view of how well (or how badly) a company implements information security. This standard is a great tool for companies whether establishing or improving information security within their organization.

The information security process traditionally has been based on sound best practices and guidelines, with the goals of preventing, detecting and containing security breaches, as well as restoration of the affected data to its previous state. While this cumulative wisdom of the ages is valid, it is also subject to various interpretations and implementations. ISO 17799 offers an achievable benchmark against which to build organizational information security.

Control Selection based on Risks Identified

ISO 17799 consists of 39 security controls, which can be used as a basis for a security risk assessment. The controls encompass all forms and types of information, whether they are electronic files, paper documents or various forms of communications such as email, fax and spoken conversations. The standard sets out a variety of hardware and software considerations, policies, procedures and organizational structures that protect a company’s information assets from a broad range of modern security threats and vulnerabilities. How organizations shape their information security programs will depend on the unique requirements and risks they face. An organization should only deploy controls that relate to, and are in proportion to, the actual risks it faces.

Controls can also more simply be described as the countermeasures for risks. Apart from knowingly accepting risks considered acceptable, or transferring those risks (through insurance) to others, there are essentially four types of control:

1. Deterrent controls reduce the likelihood of a deliberate attack.

2. Preventative controls protect vulnerabilities and make an attack unsuccessful or reduce its impact.

3. Corrective controls reduce the effect of an attack.

4. Detective controls discover attacks and trigger preventative or corrective controls.

It is essential that any controls that are implemented are cost-effective. The cost of implementing and maintaining a control should be no greater than the identified and quantified cost of the impact of the identified threat (or threats). It is not possible to provide total security against every single risk; the trade-off involves providing effective security against most risks. No board should sign off on any ISMS proposal that seeks to remove all risk from the business – the business does, after all, exist within a risk framework and, since it is impossible to exist risk-free, there is little point in proposing to eliminate every risk.

No organization should invest in information security technology (hardware or software) or implement information security management processes and procedures without having carried out an appropriate risk and control assessment that assures them that:

– The proposed investment (the total cost of the control) is the same as, or less than, the cost of the identified impact;

– The risk classification, which takes into account its probability, is appropriate for the proposed investment; and

– Mitigating the risk is a priority – i.e. all the risks with higher prioritization have already been adequately controlled and, therefore, it is appropriate now to be investing in controlling this one.

Once information security needs and requirements are identified, a suitable set of controls from ISO 17799 can be established, implemented, monitored, reviewed and improved upon in order to ensure that the specific security objectives of the organization are met.

ISO 17799 is a comprehensive information security code of practice that provides enterprises an internationally recognized and structured methodology for information security. In addition to ISO 17799, the International Organization for Standardization also published ISO 27001, which specifies a number of requirements for establishing, implementing, maintaining and improving an ISMS using the controls outlined in ISO 17799.

ISO 27001 is the formal standard against which an organization may seek independent certification of their ISMS. While certification is entirely optional, as of January 2007, over 3000 organizations world-wide were ISO 27001 certified, demonstrating their commitment to information security. Organizations may be certified compliant with ISO 27001 by a number of accredited certification bodies worldwide. ISO 27001 certification generally involves a two stage audit process, with a “table top” review of key documentation at the first stage and a more in-depth audit of the ISMS at the second stage. The certified organization would need to be re-assessed periodically by the certification body.

In summary, organizations face threats to their information assets on a daily basis. At the same time, they are becoming increasingly dependent on these assets. Technical solutions are only one portion of a holistic approach to information security. Establishing broad information security requirements in the framework of the organization’s own unique risk environment is essential.

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