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Study Paper on Standards for Auditing Information System Security

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Study Paper on Standards for Auditing Information System Security

     Formulation of IT Auditing Standards

    IT Audit Seminar organized by

    National Audit Office, China

    1 to 4 September 2004

     Paper on “Formulation of IT Auditing Standards”

    By -- Ms.Puja S Mandol and Ms. Monika Verma

    Supreme Audit Institution of India

    Introduction

    The use of computers and computer based information systems have pervaded

    deep and wide in every modern day organization. An organization must exercise control

    over these computer based information systems because the cost of errors and

    irregularities that may arise in these systems can be high and can even challenge the

    very existence of the organization. An organizations ability to survive can be severely

    undermined through corruption or destruction of its database; decision making errors

    caused by poor-quality information systems; losses incurred through computer abuses;

    loss of computer assets and their control on how the computers are used within the

    organization. Therefore managements across the world have deployed specialized

    auditors to audit their information systems to find out gaps between declared policies

    and actual use and shortcomings in the information system design and usage.

    Information Systems Audit is the process of collecting and evaluating evidence

    to determine whether a computer system has been designed to maintain data integrity,

    safeguard assets, allows organizational goals to be achieved effectively and uses the

    resources efficiently.

     The IS Auditor should see that not only adequate internal controls exist in the

    system but they also wok effectively to ensure results and achieve objectives. Internal

    controls should be commensurate with the risk assessed so as to reduce the impact of

    identified risks to acceptable levels. IT Auditors need to evaluate the adequacy of

    internal controls in computer systems to mitigate the risk of loss due to errors, fraud and

    other acts and disasters or incidents that cause the system to be unavailable

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     Formulation of IT Auditing Standards

    Auditing Standards for auditing Information Systems

    The specialized nature of Information Systems auditing and the professional

    skills and credibility necessary to perform such audits, require standards that would

    apply specifically to IS auditing. Standards, procedures and guidelines have been issued

    by various institutions, which discuss the way the auditor should go about auditing

    Information Systems.

    In line with such developments Supreme Audit Institution of India has declared

    a mission to adopt and evolve standards, guidelines and best practices for auditing in a

    computerized environment. This will lend credibility and clarity in conducting audit in

    computerized environment.

    The framework for the IS Auditing Standards provides multiple levels of

    guidance. Standards provide a framework for all audits and auditors and define the

    mandatory requirements of the audit. They are broad statement of auditors‘

    responsibilities and ensure that auditors have the competence, integrity, objectivity and

    independence in planning, conducting and reporting on their work. Guidelines provide

    guidance in applying IS Auditing Standards. The IS auditor should consider them in

    determining how to achieve implementation of the standards, use professional judgment

    in their application and be prepared to justify any departure. Procedures provide

    examples of procedures an IS auditor might follow in an audit engagement. It provides

    information on how to meet the standards when performing IS auditing work, but do not

    set requirements. The objective of the IS Auditing Guidelines and Procedures is to

    provide further information on how to comply with the IS Auditing Standards.

    While conducting Information System Audit the auditor should consider the

    issues of confidentiality, integrity and availability (CIA) and his work should be guided

    by international or respective national standards. These may include INTOSAI Auditing

    Standards, International Federation of Accountants (IFAC) Auditing Standards,

    International standards of professional audit institutions such as Information Systems

    Audit and Control Association (ISACA) and Institute of Internal auditors (IIA) and

    national auditing standards of SAI member countries.

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     Formulation of IT Auditing Standards

    Information Systems Audit and Control Association (ISACA) has laid down the

    following generic requirements for IS audit which are applicable to all categories of IS

    audits

    1. The responsibility, authority and accountability of the information systems audit

    function are to be appropriately documented in an audit.

    2. The information systems auditor is to be independent of the auditee in attitude and

    appearance.

    3. The information systems auditor is to adhere to the „Code of Professional Ethics’.

    Due professional care and observance of applicable professional auditing standards

    are to be exercised.

    4. The information systems auditor is to be technically competent, having the skills

    and knowledge necessary to perform the auditor's work and has to maintain

    technical competence through continuing professional education. 5. The information systems auditor is to plan his work to address the audit objectives.

    6. Information systems audit staff is to be appropriately supervised so as to ensure that

    audit objectives and applicable professional auditing standards are met. The audit

    findings and conclusions are to be supported by appropriate analysis and

    interpretation of sufficient, reliable, relevant and useful evidence. 7. The information systems auditor is to provide a report, in an appropriate form, to

    intended recipients upon the completion of audit work.

    8. The information systems auditor follow-up action timely taken on previous relevant

    findings.

    SAI India has adopted COBIT as a source of best practice guidance. The COBIT

    framework gives an IS Auditor an understanding of business objectives, best practices

    and recommends a commonly understood and well-respected standard reference. It

    includes Control Objectives, Control Practices and Audit Guidelines, which provides guidance for each control area on how to obtain an understanding, evaluate each control,

    assess compliance, and substantiate the risk of controls not being met.

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     Formulation of IT Auditing Standards

    Information Systems Security and Audit

    Organizations in all sectors of the economy depend upon information systems

    and communications networks, and share common requirements to protect sensitive

    information. Organizations and professional bodies‘ work towards establishing secure

    information technology systems for protecting the integrity, confidentiality, reliability,

    and availability of information.

    Defining Security Audit

    Information Systems Security Audit is an independent review and examination

    of system records, activities and related documents to determine the adequacy of system

    controls, ensure compliance with established security policy and approved operational

    procedures, detect breaches in security so as to verify whether data integrity is

    maintained, assets are safeguarded, organizational goals are achieved effectively and

    resources are used efficiently. Security audit is a systematic, measurable technical

    assessment of how security policies are built into the information systems.

    Professionalism and credibility play a very important role in the auditor‘s

    performance of Information Systems Security Audit. He should have full knowledge of

    the organization and its various functions, at times with considerable inside information.

    The three fundamental features of an Information System that gets tested in

    course of security audit are assessment of confidentiality, availability and integrity of

    the information systems assets. The principle screening variables are various

    conceivable physical and logical security threats.

    The purpose of any audit will be essentially to examine three basic compliances

    in terms of Confidentiality, Integrity and Availability (CIA)

    ? Confidentiality concerns the protection of sensitive information from

    unauthorized disclosure. Keeping in view the level of sensitivity of the data

    the stringency of controls over its access should be determined.

    ? Integrity refers to ‗the accuracy and completeness of the information as well

    as to its validity in accordance with business values and expectations. It is

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     Formulation of IT Auditing Standards

    an important audit objective as it provides assurance to the

    management as well as the users that the information can be relied and

    trusted upon. It also includes reliability, which refers to degree of

    consistency of the system to function.

    ? Availability relates to information and information systems being available

    and operational when they are needed. It also concerns safeguarding of

    necessary resources and associated capabilities. This implies that the

    organization has measures in place to ensure business continuity and timely

    recovery can be made in case of disasters.

    Why is security audit important?

    An organization is always subjected to a set of risks in every business and

    project initiative it undertakes. These include Business Risk, Strategic Risk, Operational

    Risk and Risk of legal non-compliance. The information systems, while they play

    significant role in the strategic initiatives of organizations (be it an ERP in a large auto

    company or be it an e-governance initiative) are also subjected to these risks.

    Threats can be internal or external to the organization on one hand and a result

    of some slippage or deliberate intrusion on the other. Thus besides safeguarding the

    information system, a Security Audit protects the organization‘s overall interests.

    Standardizing Security Audit Initiatives so far

    Institutions and professional bodies all over the world have issued various

    guidelines and best practices regarding Information System Security from time to time.

    British Standards (BS 7799) provides guidelines to organizations to identify, manage and minimize the range of threats to which information is regularly subjected. These

    include internal threats, external threats, accidents, malicious actions and industrial

    sabotage.

     International Organization for Standardization (ISO/IEC 17799) guidelines

    state that the management should set a clear policy direction and demonstrate support

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     Formulation of IT Auditing Standards

    for, and commitment to, information security through the issue and maintenance

    of an information security policy across the organization.

     Center for Internet Security (CIS) has a mission to help organizations reduce the risk of business and e-commerce disruptions resulting from inadequate technical

    security controls. CIS benchmarks support high level standards that deal with the "Why,

    Who, When, and Where" aspects of IT security by detailing "How" to secure an ever

    widening array of workstations, servers, network devices, and software applications in

    terms of technology specific controls.

    Generally Accepted System Security Principles (GASSP) (which is sponsored

    2SF) promotes good practice and by the International Information Security Foundation (I

    provide the authoritative point of reference and legal reference for information security

    principles, practices and opinions.

    National Institute of Standards and Technology (NIST) has published

    guidelines to provide a standardized approach for assessing the effectiveness of the

    management, operational, and technical security controls in an information system and

    for determining the business or mission risk to an agency's operations and assets

    brought about by the operation of that system. Under the Computer Security Act of

    1987 (P.L. 100-235), the Computer Security Division of the Information Technology

    Laboratory (ITL) develops computer security prototypes, tests, standards, and

    procedures to protect sensitive information from unauthorized access or modification.

    Focus areas include cryptographic technology and applications, advanced authentication,

    public key infrastructure, internetworking security, criteria and assurance, and security

    management and support. The NIST IPsec Project is concerned with providing authentication, integrity and confidentiality security services at the Internet (IP) Layer,

    for both the current IP protocol (IPv4) and the next generation IP protocol (IPv6).

     Commonly Accepted Security Practices & Recommendations (CASPR)

    provides advice about how to use technologies, products, and methodologies to secure

    the IT environment, through papers written and vetted by a community of experts.

    Bureau of Indian Standards (BIS) describes Information Security Policy as one of the main responsibilities of the management of an organization and thus is a pointer

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     Formulation of IT Auditing Standards

    to the roles and functions of the auditor. It talks about identifying all business

    critical information and evaluating their existing classification, risk assessment,

    reviewing the security controls to mitigate the risks and suggesting improvements in the

    Information Security Management System.

    Legal enactments

    In 1996, United Nations Commission on International Trade Law (UNCITRAL)

    adopted Model Law on Electronic Commerce. The Model Law facilitates the use of

    modern means of communications and storage of information, such as electronic data

    interchange (EDI), electronic mail and telecopy, with or without the use of paper-based

    concepts such as ―writing‖, ―signature‖ or ―original‖. The General Assembly of the

    United Nations by resolution on 30th January 1997 adopted the Model Law on

    Electronic Commerce. This resolution recommended inter alia that all States should

    give favorable consideration to the said Model Law when they enact or revise their laws,

    in view of the need for uniformity of the law applicable to alternatives to paper-based

    methods of communication and storage of information.

    In India the IT Act 2000 has provided legal recognition for transactions carried

    out by means of electronic data interchange and other means of electronic

    communication, which involve the use of alternatives to paper-based methods of

    communication and storage of information, to facilitate electronic filing of documents

    with the Government agencies.

    Standards for auditing Information Systems Security

     In addition the generic auditing standards to be followed while auditing an

    Information Systems, guidelines, practices or benchmarks are necessary to specifically

    address issues relating to audit of Information Systems Security. We will discuss this

    issue in respect of three distinct domains of Information System Security viz.

    Operations System Security, Telecommunication System or Networking Security and

    Access Control Security which are the sub-themes in this seminar.

    1. Operational Systems Security

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     Formulation of IT Auditing Standards

    Operational Systems Security Audit is a process to evaluate the security

    features of an information system in an organization. This includes examining the

    internal controls within the system and to what extent are they effective in achieving the

    objectives of safeguarding of assets and of data integrity and availability. These controls

    could be preventive, detective, corrective or response-based in nature. The following

    specific areas come under the scope of a comprehensive security audit of the

    operational system Organizational Security, Asset classification and control, Physical and Environmental Security, Personnel security, System Development and Maintenance,

    Business Continuity Management policies and Compliance to legal framework.

    The auditor should examine the following issues in respect of procedures and

    policies laid down by the organization

    a. Organizational security Auditor should check that the management has

    defined a security policy and is committed to implementation of the same,

    continuously improve upon its effectiveness, spreading awareness among the

    users and ensuring availability of resources. He should examine how clearly and

    appropriately the mission statement defines the purpose and goals of the policy

    to preserve the confidentiality, integrity and availability of computing resources.

    He should see that

    i. The comprehensive security policy approved by the management is in place,

    documented and communicated to and understood by all concerned.

    ii. It defines clearly the responsibilities of the members of the organizations.

    iii. The policy is reviewed regularly and amended if required with appropriate

    authorization.

    iv. The procedures are documented and followed as laid down.

    v. Adequate controls are in place to ensure the security of organization

    information processing facilities and assets either accessed by third parties or

    outsourced.

    vi. The policies and procedures are having their intended effect and the

    confidentiality, integrity and availability of the system and data are

    maintained and assets are safeguarded.

    b. Asset classification and control Auditor should examine the classification

    system adopted to maintain appropriate protection of organizational assets both

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     Formulation of IT Auditing Standards

    physical and logical. These models classify the assets and information into

    various levels, which describes that who will be allowed access to what resource

    classifications. For e.g. in military circles, it is common for information to be

    classified into five levels viz. top secret, secret, confidential, restricted and

    unclassified and accordingly their information also mirror the principles which

    are in practice. Access information at each level is decided as per the need- to-

    know principle. The level of controls required, determines how elaborate a

    classification should be.

     Similarly with reference to the network where there are multiple users, at

    multiple destinations, including those outside the organization, the IS auditor

    should examine whether the terminals or network elements are classified

    appropriately, say for example a company deploys an IP system, with what

    rationale the network contents are classified as unclassified, shared, company

    only and confidential. There can be alternative classification systems.

    The auditor would need to map these classifications with segregation of

    duties, creation of users, access levels as defined by the organization. The

    auditor should study the following issues:

    i. Inventory of all the assets is maintained and is kept up to date both

    hardcopy as well as electronically.

    ii. The database of the information assets is maintained along with the

    designated owner of the asset.

    iii. Classified information is labeled, stored and handled strictly in accordance

    with the classification level assigned to that information.

    c. Personnel Security The auditor should satisfy himself with respect to the

    organization‘s policy to include security roles in job description, making it

    binding on the employees and steps taken to make them aware of threats and

    concerns. He should examine the comprehensiveness of the policy, whether it

    addresses the issue of violations of the security policy by the employees. He

    should make an attempt to address the following issues:

    i. Is there a formal system for reporting and taking preventive and remedial

    actions in place, which works towards minimizing the damage from such

    incidents? Are the users following a formal incident response mechanism?

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     Formulation of IT Auditing Standards

    ii. Is there an Acceptable Use Policy for IT resources and are users

    complying with the same?

    iii. Is there a mechanism in place to defend the system against techno-vandalism? iv. What are the steps taken to make the users aware of the threats and

    safeguards to the information system and the required remedial measures?

    d. Physical and Environmental Security The auditor should examine whether

    the steps taken by the organization adequately prevent unauthorized physical

    access and interference to the business premises and information assets and

    prevent loss, damage or theft. To satisfy himself of the adequacy of procedures

    in this respect, the auditor should see the following issues:

    i. The equipments are maintained in accordance with the documented

    procedures.

    ii. Secured areas are created with restricted physical access and guidelines are given to conduct activities in these area.

    iii. Logs of entry and exit are maintained in the system.

    iv. Adequate steps are taken to secure equipments at other related sites. v. The equipments at site are protected from natural disasters like fire, flood,

    earthquakes etc. and man-made disasters like terrorist attacks, power

    problems etc.

    vi. Necessary facilities like air-conditioning, dust-free environment are in

    place for smooth functioning of the system.

    vii. The equipments are supported by appropriate maintenance facilities from

    qualified engineers.

    e. Communications and Operations Management Controls should be in place to

    secure all the three stages of data communication viz. assembly, dispatch and

    retrieval of the data in a network. The auditor should see if a multi-layered

    security model consisting of some or all of the following: border router filtering,

    firewalls, intrusion detection systems, domain based security system, host

    protection, cryptography, physical security, incidence response, defined

    standards and active monitoring and testing. Security standards would cover

    examining operating systems, system software, servers, database, personnel,

    application software, networking protocol etc.

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