Extreme programming
Extreme programming (XP) is the most well known and widely implemented agile development method for software products. XP uses a test-driven and bottom-up software development approach.
Extranet
A private network that uses web technology, permitting the sharing of portions of an enterprise’s information or operations with suppliers, vendors, partners, customers, or other enterprises.
F
Failover
(1) The capability to switch over automatically without human intervention or warning to a redundant or standby information system upon the failure or abnormal termination of the previously active system. (2) It is a backup concept in that when the primary system fails, the backup system is automatically activated.
Fail-safe
An automatic protection of programs and/or processing systems when hardware or software failure is detected in a computer system. It is a condition to avoid compromise in the event of a failure or have no chance of failure. This is a technical and corrective control.
Fail-safe default
Asserts that access decisions should be based on permission rather than exclusion. This equates to the condition in which lack of access is the default, and the “protection scheme” recognizes permissible actions rather than prohibited actions. Also, failures due to flaws in exclusion-based systems tend to grant (unauthorized) permissions, whereas permission-based systems tend to fail-safe with permission denied.
Fail-secure
The system preserves a secure condition during and after an identified failure.
Fail-soft
A selective termination of affected nonessential processing when hardware or software failure is determined to be imminent in a computer system. A computer system continues to function because of its resilience. Examples of its application can be found in distributed data processing systems. This is a technical and corrective control.
Fail-stop processor
A processor that can constrain the failure rate and protects the integrity of data. However, it is likely to be more vulnerable to denial-of-service (DoS) attacks.
Failure
It is a discrepancy between external results of a program’s operation and software product requirements. A software failure is evidence of software faults.
Failure access
A type of incident in which unauthorized access to data results from hardware or software failure.
Failure control
A methodology used to detect imminent hardware or software failure and provide fail-safe or fail-soft recovery in a computer system (ANSI and IBM).
Failure rate
The number of times the hardware ceases to function in a given time period.
Fallback procedures
(1) In the event of a failure of transactions or the system, the ability to fallback to the original or alternate method for continuation of processing. (2) The ability to go back to the original or alternate method for continuation of computer processing.
False acceptance
When a biometric system incorrectly identifies an individual or incorrectly verifies an impostor against a claimed identity.
False acceptance rate (FAR)
The probability that a biometric system will incorrectly identify an individual or will fail to reject an impostor. The rate given normally assumes passive impostor attempts. The FAR is stated as the ratio of the number of false acceptances divided by the number of identification attempts.
False match rate
Alternative to false acceptance rate. Used to avoid confusion in applications that reject the claimant if their biometric data matches that of an applicant.
False negative
(1) An instance of incorrectly classifying malicious activity or content as benign. (2) An instance in which a security tool intended to detect a particular threat fails to do so. (3) When a tool does not report a security weakness where one is present.
False non-match rate
Alternative to false rejection rate. Used to avoid confusion in applications that reject the claimant if their biometric data matches that of an applicant.
False positive
(1) An instance in which a security tool incorrectly classifies benign activity or content as malicious. (2) When a tool reports a security weakness where no weakness is present. (3) An alert that incorrectly indicates that malicious activity is occurring.
False positive rate
The number of false positives divided by the sum of the number of false positives and the number of true positives.
False rejection
When a biometric system fails to identify an applicant or fails to verify the legitimate claimed identity of an applicant.
False rejection rate (FRR)
The probability that a biometric system will fail to identify an applicant, or verify the legitimate claimed identity of an applicant. The FRR is stated as the ratio of the number of false rejections divided by the number of identification attempts.
Fault
A physical malfunction or abnormal pattern of behavior causing an outage, error, or degradation of communications services on a communications network. Fault detection, error recovery, and failure recovery must be built into a computer system to tolerate faults.
Fault injection testing
Unfiltered and invalid data are injected as input into an application program to detect faults in resource operations and execution functions.
Fault management
The prevention, detection, reporting, diagnosis, and correction of faults and fault conditions. Fault management includes alarm surveillance, trouble tracking, fault diagnosis, and fault correction.
Fault-tolerance mechanisms
The ability of a computer system to continue to perform its tasks after the occurrence of faults and operate correctly even though one or more of its component parts are malfunctioning. Synonymous with resilience.
Fault tolerant controls
The ability of a processor to maintain effectiveness after some subsystems have failed. These are hardware devices or software products such as disk mirroring or server mirroring aimed at reducing loss of data due to system failures or human errors. It is the ability of a processor to maintain effectiveness after some subsystems have failed. This is a technical and preventive control and ensures availability control.
Fault-tolerant programming
Fault tolerant programming is robust programming plus redundancy features, and is partially similar to N-version programming.
Feature
An advantage attributed to a system.
Federated trust
Trust established within a federation, enabling each of the mutually trusting realms to share and use trust information (e.g., credentials) obtained from any of the other mutually trusting realms.
Federation
A collection of realms (domains) that have established trust among themselves. The level of trust may vary, but typically include authentication and may include authorization.
Fetch protection
A system-provided restriction to prevent a program from accessing data in another user’s segment of storage. This is a technical and preventive control.
Fiber-optic cable
A method of transmitting light beams along optical fibers. A light beam, such as that produced in a laser, can be modulated to carry information. A single fiber-optic channel can carry significantly more information than most other means of information transmission. Optical fibers are thin strands of glass or other transparent material.