T

TACACS (Terminal Access Controller Access Control System)

A UDP-based access control protocol that provides authentication, authorization, and accounting.

Take-Grant model

A security model that specifies the rights that a subject can transfer to or from another subject or object.

TCB (Trusted Computing Base)

The total combination of protection mechanisms within a computer system, including hardware, firmware, and software, which is responsible for enforcing a security policy.

TCP (Transmission Control Protocol)

A connection-oriented network protocol that provides reliable delivery of packets over a network.

TCSEC (Trusted Computer System Evaluation Criteria)

Commonly known as the Orange Book. Formal systems evaluation criteria developed for the U.S. Department of Defense by the National Computer Security Center (NCSC) as part of the Rainbow Series.

Teardrop attack

A type of stack overflow attack that exploits vulnerabilities in the IP protocol.

Technical (or logical) controls

Hardware and software technology used to implement access control.

Telnet

A network protocol used to establish a command line interface on another system over a network. See also SSH.

Threat

Any natural or man-made circumstance or event that could have an adverse or undesirable impact, whether minor or major, on an organizational asset.

TNI (Trusted Network Interpretation)

Commonly known as the Red Book (of the Rainbow Series; see also TCSEC). Addresses confidentiality and integrity in trusted computer/ communications network systems.

Token

A hardware device used in two-factor authentication.

Token Ring

A star-topology network transport protocol.

Trademark

As defined by the U.S. Patent and Trademark Office (PTO), a trademark is “any word, name, symbol, or device, or any combination, used, or intended to be used, in commerce to identify and distinguish the goods of one manufacturer or seller from goods manufactured or sold by others.”

Trade secret

Proprietary or business-related information which a company or individual uses and has exclusive rights to.

Traffic analysis

A method of attack whereby an attacker observes network traffic patterns in order to make deductions about network utilization, architecture, behavior, or other discernable characteristic.

Transient

A momentary electrical line noise disturbance.

Transposition cipher

Ciphers that rearrange bits, characters, or character blocks in plaintext to produce ciphertext.

Trap door

A feature within a program that performs an undocumented function, usually a security bypass such as an elevation of privilege.

Trojan horse

A program that purports to perform a given function, but which actually performs some other, and usually malicious, function.

Trusted computer system

A system that employs all necessary hardware and software assurance measures and meets the specified requirements for reliability and security.

Trusted network interpretation (TNI)

The Rainbow Series document that addresses confidentiality and integrity in trusted computer/communications network systems. See also TCSEC.

Trusted path

A direct communications path between the user and the TCB that does not require interaction with untrusted applications or operating system layers.

Trusted recovery

Safeguards to prevent the disclosure of information during the recovery of a system after a failure.

Two-Factor authentication

An authentication method that requires two ways of establishing identity.