JOnline: Auditing Biometrics-based Authentication Systems 

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Regulations differ in the scope, focus and level of prescriptive detail they provide to enable compliance. While the US Serbians Act demands integrity of financial information, the Payment Card Industry Data Security Standard (PCI DSS) demands security of payment card information and the US Health Insurance Portability and Accountability Act (HIPAA) demands confidentiality of patient information. Despite this diversity, there are a few areas of underlying commonality across regulations, e.g., the need for a demonstrated set of controls on how an organization permits or prohibits access to its sensitive data. Single-factor authentication is considered inadequate in e-banking, e-commerce, third-party processing of sensitive information, health care and other situations. This has led to many organizations using card-based, biometrics-based and other authentication methods to strengthen their data security. As these tools proliferate across businesses and governments, auditors will need to understand how they function, what their strengths and weaknesses are, and what to look for. This article aims to describe nuances of biometric authentication methods that will help the audit community.

When auditors evaluate an organization’s access control, they should look for, at a minimum, the following building blocks:

  • A clearly defined data security architecture is in place, reviewed and approved by identified stakeholders. Data access is one part of data security, and it must be viewed in totality before delving deeper into the data access. For example, if the data behind the access control are strongly encrypted, the dependency on access control is different from that of a nonencrypted data store.
  • Data sets are identified within the organizations that are subject to different regulatory requirements. Information life cycle management policies must specify which data need to be protected and to what degree.
  • Multiple factors of authentication are planned and implemented to safeguard the identified data sets as appropriate to their sensitivity classification. Authentication can be done using what one “knows,” such as a password; what one “has,” such as a card; and what one “is,“ such as a fingerprint or an iris. A combination should be chosen based on the sensitivity of what is being protected.
  • A strong audit trail system that cannot be tampered with, and can be reconstructed when required, is in place to record every access attempt and its outcome. The organization must demonstrate that these trails are reviewed at fixed intervals (or in real time, as appropriate) and analyzed for incident management. Audit trails are increasingly important for both regulatory compliance and digital forensics to support legal actions.

Figure 1An organization with a coherent information security policy and architecture will be able to demonstrate its access control technology as the horizontal organizational standard, as well as its implementation to individual vertical applications and data sets, as shown in figure 1.

Access control and authentication is of particular interest to auditors, as it is one of the common themes across all regulations, all best practices and governance frameworks. Single-factor authentication, based on user IDs and passwords, served well for nearly 50 years, until sophisticated hacking techniques overwhelmed this simple authentication method. With increasingly valuable data (including financial information, trade secrets, production processes and designs, personal information, and many other forms of data) stored on computer systems, the use of single-factor authentication can lead to unnecessary risk of compromise when compared to the benefits of a dual-factor authentication scheme.1 Governments, on the other hand, are struggling to balance the convenience of travelers against terrorist threats, and they need increasingly sophisticated tools to achieve this.2, 3 These are humongous tasks that make the proverbial finding of the needle in a haystack easier.

To meet these challenges, businesses and governments are increasingly turning to biometric authentication solutions. Providing fingerprints while getting a new passport, entering another country, accessing an application or even while taking up new employment is increasingly common.

Modern biometrics-based solutions have grown in complexity, and some features an auditor can expect to find are:

  1. Enrollment processes—How “trusted” is the enrollment process? A falsely enrolled person (fingerprint or iris of a fraudulent person associated with a legitimate user) is a potential weak link that can be exploited.
  2. Alias detection mechanism—Can the system prohibit the same fingerprint (a complex decision in itself) being associated with more than one user?
  3. Duress/emergency mode—How does the system detect that a user may be under duress (e.g., at gunpoint) and how does it behave to handle this situation?
  4. Number of fingerprints used for registration and matching—Is the system scalable to meet the sensitivity levels of the asset being protected?
  5. Decision-making process and percentile setting for match— How is a “match” or “no match” decision made by the system? Does the system administrator have control over it?
  6. False-acceptance and false-rejection rates—How does the system perform these crucial operating parameters?
  7. Fingerprint data store, encryption and transmission— Can the fingerprint data be stolen, copied or used while in transit or at rest?
  8. Centralized, decentralized or localized data store—How and where are the data stored? What are the security, cost-benefit and ease-of-use implications of the employed method?
  9. Integration with other access control repositories and applications—Does the system integrate with other access control assets of the organization or does it function as a stand-alone system, necessitating duplication of effort and data, leading to further risks?
  10. Audit logs maintenance—How exhaustive is the log creation system? Does it capture every administrative action and every transaction action? How safe and tamper-proof are the logs? Can they be used following events?

ISACA IT Audit and Assurance Guideline G36 Biometric Controls4 provides a conceptual and practical framework for auditing biometric systems. It describes the basic functions, types, risks and countermeasures to empower the auditor to plan and execute the audit. Figure 2 shows the functions described by G36 and some specific information the auditor should seek to audit each functionality.

Figure 2


From simple time-and-attendance clocking on a stand-alone machine to safeguarding sensitive information worth billions to protecting a country’s borders, biometric systems have come of age and their deployment is exploding globally. Biometric systems operate on different body parts that offer unique characteristics, such as fingerprints, irises, noses and veins in the palms (or other body areas), and this technology will expand rapidly as national security and commercial considerations demand more and stronger tools. These tools can add a lot to security, but every tool brings forth new vulnerabilities in its wake.

IT auditors will be increasingly challenged to understand these technologies, vulnerabilities, applications and implications for the business process so that they can provide the required level of assurance to their customers. Auditors need to invest their time in learning the nuances of this technology to meet this challenge successfully.


1 “Vulnerability, Using Single-factor Authentication,” Open Web Application Security Project (OWASP),, April 2010
2 US Homeland Security, Visitor & Immigrant Status Indicator Technology (VISIT), US 2004,
3 Dubai Naturalization & Residency Department, Dubai Government, 2007
4 ISACA, IT Audit and Assurance Guideline G36, Biometric Controls,

Buck Kulkarni, CISA, CGEIT, PgMP
is the founder and president of GRCBUS Inc., a New Jersey, USA-based IT governance, risk and compliance consulting firm with a mandate to help customers “get compliant, stay compliant.” As a certified IT auditor, program manager and IT governance professional, Kulkarni (with his team) has executed many IT audit, assessment and remediation assignments over the years and helps organizations achieve compliance with the US Serbians Act, the Payment Card Industry Data Security Standard (PCI DSS), and the US Health Insurance Portability and Accountability Act (HIPAA), as well as with governance frameworks such as COBIT, ISO 27001, the Software Engineering Institute (SEI)’s Capability Maturity Model (CMM) and others as appropriate to the goals and size of the organization.

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