access A subject’s ability to view, modify, or communicate with an object. Access enables the flow of information between the subject and the object.

access control Mechanisms, controls, and methods of limiting access to resources to authorized subjects only.

access control list (ACL) A list of subjects that are authorized to access a particular object. Typically, the types of access are read, write, execute, append, modify, delete, and create.

access control mechanism Administrative, physical, or technical control that is designed to detect and prevent unauthorized access to a resource or environment.

accountability A security principle indicating that individuals must be identifiable and must be held responsible for their actions.

accredited A computer system or network that has received official authorization and approval to process sensitive data in a specific operational environment. There must be a security evaluation of the system’s hardware, software, configurations, and controls by technical personnel.

add-on security Security protection mechanisms that are hardware or software retrofitted to a system to increase that system’s protection level.

administrative controls Security mechanisms that are management’s responsibility and referred to as “soft” controls. These controls include the development and publication of policies, standards, procedures, and guidelines; the screening of personnel; security-awareness training; the monitoring of system activity; and change control procedures.

aggregation The act of combining information from separate sources of a lower classification level that results in the creation of information of a higher classification level, which the subject does not have the necessary rights to access.

AIC triad The three security principles: availability, integrity, and confidentiality. Sometimes also presented as CIA: confidentiality, integrity, and availability.

annualized loss expectancy (ALE) A dollar amount that estimates the loss potential from a risk in a span of a year.

single loss expectancy (SLE) × annualized rate of occurrence (ARO) = ALE

antimalware Software whose principal functions include the identification and mitigation of malware; also known as antivirus, although this term could be specific to only one type of malware.

annualized rate of occurrence (ARO) The value that represents the estimated possibility of a specific threat taking place within a one-year timeframe.

assurance A measurement of confidence in the level of protection that a specific security control delivers and the degree to which it enforces the security policy.

attack An attempt to bypass security controls in a system with the mission of using that system or compromising it. An attack is usually accomplished by exploiting a current vulnerability.

attribute-based access control (ABAC) An access control model in which access decisions are based on attributes of any component of or action on the system.

audit A systematic assessment of significant importance to the organization that determines whether the system or process being audited satisfies some external standards.

audit trail A chronological set of logs and records used to provide evidence of a system’s performance or activity that took place on the system. These logs and records can be used to attempt to reconstruct past events and track the activities that took place, and possibly detect and identify intruders.

authenticate To verify the identity of a subject requesting the use of a system and/or access to network resources. The steps to giving a subject access to an object should be identification, authentication, and authorization.

authorization Granting access to an object after the subject has been properly identified and authenticated.

availability The reliability and accessibility of data and resources to authorized individuals in a timely manner.

back door An undocumented way of gaining access to a computer system. After a system is compromised, an attacker may load a program that listens on a port (back door) so that the attacker can enter the system at any time. A back door is also referred to as a trapdoor.

back up Copy and move data to a medium so that it may be restored if the original data is corrupted or destroyed. A full backup copies all the data from the system to the backup medium. An incremental backup copies only the files that have been modified since the previous backup. A differential backup backs up all files since the last full backup.

baseline The minimum level of security necessary to support and enforce a security policy.

Bell-LaPadula model The model uses a formal state transition model that describes its access controls and how they should perform. When the system must transition from one state to another, the security of the system should never be lowered or compromised. See also multilevel security, simple security property, and star property (*-property).

Biba model A formal state transition system of computer security policy that describes a set of access control rules designed to ensure data integrity.

biometrics When used within computer security, identifies individuals by physiological characteristics, such as a fingerprint, hand geometry, or pattern in the iris.

blacklist A set of known-bad resources such as IP addresses, domain names, or applications.

browsing Searching through storage media looking for specific information without necessarily knowing what format the information is in. A browsing attack is one in which the attacker looks around a computer system either to see what looks interesting or to find specific information.

brute-force attack An attack that continually tries different inputs to achieve a predefined goal, which can be used to obtain credentials for unauthorized access.

business impact analysis (BIA) A functional analysis in which a team collects data, documents business functions, develops a hierarchy of business functions, and applies a classification scheme to indicate each individual function’s criticality level.

callback A procedure for identifying a system that accessed an environment remotely. In a callback, the host system disconnects the caller and then dials the authorized telephone number of the remote terminal in order to reestablish the connection. Synonymous with dialback.

capability A capability outlines the objects a subject can access and the operations the subject can carry out on the different objects. It indicates the access rights for a specific subject; many times, the capability is in the form of a ticket.

capability maturity model integration (CMMI) A process model that captures the organization’s maturity and fosters continuous improvement.

certification The technical evaluation of the security components and their compliance for the purpose of accreditation. A certification process can use safeguard evaluation, risk analysis, verification, testing, and auditing techniques to assess the appropriateness of a specific system processing a certain level of information within a particular environment. The certification is the testing of the security component or system, and the accreditation is the approval from management of the security component or system.

challenge/response method A method used to verify the identity of a subject by sending the subject an unpredictable or random value. If the subject responds with the expected value in return, the subject is authenticated.

change management A business process aimed at deliberately regulating the changing nature of business activities such as projects.

ciphertext Data that has been encrypted and is unreadable until it has been converted into plaintext.

Clark-Wilson model An integrity model that addresses all three integrity goals: prevent unauthorized users from making modifications, prevent authorized users from making improper modifications, and maintain internal and external consistency through auditing.

classification A systematic arrangement of objects into groups or categories according to a set of established criteria. Data and resources can be assigned a level of sensitivity as they are being created, amended, enhanced, stored, or transmitted. The classification level then determines the extent to which the resource needs to be controlled and secured, and is indicative of its value in terms of information assets.

cleartext In data communications, cleartext is the form of a message or data, which is transferred or stored without cryptographic protection.

cloud computing The use of shared remote computing devices for the purpose of providing improved efficiencies, performance, reliability, scalability, and security.

collusion Two or more people working together to carry out a fraudulent activity. More than one person would need to work together to cause some type of destruction or fraud; this drastically reduces its probability.

communications security Controls in place to protect information as it is being transmitted, especially by telecommunications mechanisms.

compartment A class of information that has need-to-know access controls beyond those normally provided for access to confidential, secret, or top-secret information. A compartment is the same thing as a category within a security label. Just because a subject has the proper clearance does not mean it has a need to know. The category, or compartment, of the security label enforces the subject’s need to know.

compensating controls Controls that are alternative procedures designed to reduce the risk. They are used to “counterbalance” the effects of an internal control weakness.

compromise A violation of the security policy of a system or an organization such that unauthorized disclosure or modification of sensitive information occurs.

computer fraud Computer-related crimes involving deliberate misrepresentation, modification, or disclosure of data in order to compromise a system or obtain something of value.

confidentiality A security principle that works to ensure that information is not disclosed to unauthorized subjects.

configuration management An operational process aimed at ensuring that systems and controls are configured correctly and are responsive to the current threat and operational environments.

confinement Controlling information in a manner that prevents sensitive data from being leaked from a program to another program, subject, or object in an unauthorized manner.

content distribution network Multiple servers distributed across a large region, each of which provides content that is optimized for users closest to it. These networks are not only used to improve the user experience but also to mitigate the risk of denial-of-service attacks.

contingency plan A plan put in place before any potential emergencies, with the mission of dealing with possible future emergencies. It pertains to training personnel, performing backups, preparing critical facilities, and recovering from an emergency or disaster so that business operations can continue.

continuous monitoring Maintaining ongoing awareness of information security, vulnerabilities, and threats to support organizational risk management decisions.

control zone The space within a facility that is used to protect sensitive processing equipment. Controls are in place to protect equipment from physical or technical unauthorized entry or compromise. The zone can also be used to prevent electrical waves carrying sensitive data from leaving the area.

converged protocol Protocols that started off independent and distinct from one another but over time converged to become one.

copyright A legal right that protects the expression of ideas.

cost/benefit analysis An assessment that is performed to ensure that the cost of a safeguard does not outweigh the benefit of the safeguard. Spending more to protect an asset than the asset is actually worth does not make good business sense. All possible safeguards must be evaluated to ensure that the most security-effective and cost-effective choice is made.

countermeasure A control, method, technique, or procedure that is put into place to prevent a threat agent from exploiting a vulnerability. A countermeasure is put into place to mitigate risk. Also called a safeguard or control.

covert channel A communications path that enables a process to transmit information in a way that violates the system’s security policy.

covert storage channel A covert channel that involves writing to a storage location by one process and the direct or indirect reading of the storage location by another process. Covert storage channels typically involve a resource (for example, sectors on a disk) that is shared by two subjects at different security levels.

covert timing channel A covert channel in which one process modulates its system resource (for example, CPU cycles), which is interpreted by a second process as some type of communication.

cryptanalysis The practice of breaking cryptosystems and algorithms used in encryption and decryption processes.

cryptography The science of secret writing that enables storage and transmission of data in a form that is available only to the intended individuals.

cryptology The study of cryptography and cryptanalysis.

cryptosystem The hardware or software implementation of cryptography.

data at rest Data that resides in external or auxiliary storage devices such as hard disk drives, solid-state drives, or DVDs.

data classification Assignments to data that indicate the level of availability, integrity, and confidentiality that is required for each type of information.

data custodian An individual who is responsible for the maintenance and protection of the data. This role is usually filled by the IT department (usually the network administrator). The duties include performing regular backups of the data; implementing security mechanisms; periodically validating the integrity of the data; restoring data from backup media; and fulfilling the requirements specified in the company’s security policy, standards, and guidelines that pertain to information security and data protection.

Data Encryption Standard (DES) Symmetric key encryption algorithm that was adopted by the government as a federal standard for protecting sensitive unclassified information. DES was later replaced with Advanced Encryption Standard (AES).

data in transit (or data in motion) Data that is moving between computing nodes over a data network such as the Internet.

data in use Data that temporarily resides in primary storage such as registers, caches, or RAM while the CPU is using it.

data leak prevention (DLP) The actions that organizations take to prevent unauthorized external parties from gaining access to sensitive data.

data mining The analysis of the data held in data warehouses in order to produce new and useful information.

data remanence A measure of the magnetic flux density remaining after removal of the applied magnetic force, which is used to erase data. Refers to any data remaining on magnetic storage media.

data warehousing The process of combining data from multiple databases or data sources into a large data store for the purpose of providing more extensive information retrieval and data analysis.

database shadowing A mirroring technology used in databases, in which information is written to at least two hard drives for the purpose of redundancy.

declassification An administrative decision or procedure to remove or reduce the security classification information.

dedicated security mode The mode in which a system operates if all users have the clearance or authorization to access, and the need to know about, all data processed within the system. All users have been given formal access approval for all information on the system and have signed nondisclosure agreements pertaining to this information.

degauss Process that demagnetizes magnetic media so that a very low residue of magnetic induction is left on the media. Used to effectively erase data from media.

Delphi technique A group decision method used to ensure that each member of a group gives an honest and anonymous opinion pertaining to the company’s risks.

denial of service (DoS) Any action, or series of actions, that prevents a system, or its resources, from functioning in accordance with its intended purpose.

DevOps The practice of incorporating developers and members of operations and quality assurance (QA) staff into software development projects to align their incentives and enable frequent, efficient, and reliable releases of software products.

dial-up The service whereby a computer terminal can use telephone lines, usually via a modem, to initiate and continue communication with another computer system.

dictionary attack A form of attack in which an attacker uses a large set of likely combinations to guess a secret, usually a password.

digital signature An electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified.

disaster recovery plan A plan developed to help a company recover from a disaster. It provides procedures for emergency response, extended backup operations, and post-disaster recovery when an organization suffers a loss of computer processing capability or resources and physical facilities.

discretionary access control (DAC) An access control model and policy that restricts access to objects based on the identity of the subjects and the groups to which those subjects belong. The data owner has the discretion of allowing or denying others access to the resources it owns.

Distributed Network Protocol 3 (DNP3) A communications protocol designed for use in SCADA systems, particularly those within the power sector, that does not include routing functionality.

domain The set of objects that a subject is allowed to access. Within this domain, all subjects and objects share a common security policy, procedures, and rules, and they are managed by the same management system.

due care Steps taken to show that a company has taken responsibility for the activities that occur within the corporation and has taken the necessary steps to help protect the company, its resources, and employees.

due diligence The process of systematically evaluating information to identify vulnerabilities, threats, and issues relating to an organization’s overall risk.

duress The use of threats or violence against someone in order to force them to do something they don’t want to do.

egress monitoring Maintaining awareness of the information that is flowing out of a network, whether it appears to be malicious or not.

electronic discovery (e-discovery) The process of producing for a court or external attorney all electronically stored information pertinent to a legal proceeding.

electronic vaulting The transfer of backup data to an offsite location. This process is primarily a batch process of transmitting data through communications lines to a server at an alternative location.

emanations Electrical and electromagnetic signals emitted from electrical equipment that can transmit through the airwaves. These signals carry information that can be captured and deciphered, which can cause a security breach. These are also called emissions.

encryption The transformation of plaintext into unreadable ciphertext.

end-to-end encryption A technology that encrypts the data payload of a packet.

exposure An instance of being exposed to losses from a threat. A weakness or vulnerability can cause an organization to be exposed to possible damages.

exposure factor The percentage of loss a realized threat could have on a certain asset.

failover A backup operation that automatically switches to a standby system if the primary system fails or is taken offline. It is an important fault-tolerant function that provides system availability.

fail-safe A functionality that ensures that when software or a system fails for any reason, it does not compromise anyone’s safety. After a failure, a fail-safe electronic lock might default to an unlocked state, which would prevent it from interfering with anyone trying to escape in an emergency.

fail-secure A functionality that ensures that when software or a system fails for any reason, it does not end up in a vulnerable state. After a failure, a fail-secure lock might default to a locked state, which would ensure the security of whatever it is protecting.

Fibre Channel over Ethernet (FCoE) A converged protocol that allows Fibre Channel frames to ride over Ethernet networks.

firmware Software instructions that have been written into read-only memory (ROM) or a programmable ROM (PROM) chip.

formal security policy model A mathematical statement of a security policy. When an operating system is created, it can be built upon a predeveloped model that lays out how all activities will take place in each and every situation. This model can be expressed mathematically, which is then translated into a programming language.

formal verification Validating and testing of highly trusted systems. The tests are designed to show design verification, consistency between the formal specifications and the formal security policy model, implementation verification, consistency between the formal specifications, and the actual implementation of the product.

gateway A system or device that connects two unlike environments or systems. The gateway is usually required to translate between different types of applications or protocols.

guidelines Recommended actions and operational guides for users, IT staff, operations staff, and others when a specific standard does not apply.

handshaking procedure A dialog between two entities for the purpose of identifying and authenticating the entities to one another. The dialog can take place between two computers or two applications residing on different computers. It is an activity that usually takes place within a protocol.

honeynet A network connecting two or more honeypots that is created for the sole purpose of luring an attacker in order to compromise it.

honeypot A computer set up as a sacrificial lamb on the network in the hope that attackers will attack this system instead of actual production systems.

identification A subject provides some type of data to an authentication service. Identification is the first step in the authentication process.

Identity as a Service (IDaaS) A type of Software as a Service (SaaS) offering that normally provides single sign-on (SSO), federated identity management (IdM), and password management services.

inference The ability to derive information not explicitly available.

information owner The person who has final corporate responsibility of data protection and would be the one held liable for any negligence when it comes to protecting the company’s information assets. The person who holds this role—usually a senior executive within the management group of the company—is responsible for assigning a classification to the information and dictating how the information should be protected.

Integrated Product Team (IPT) A multidisciplinary software development team with representatives from many or all the stakeholder populations.

integrity A security principle that makes sure that information and systems are not modified maliciously or accidentally.

Internet Small Computer System Interface (iSCSI) A converged protocol that encapsulates SCSI data in TCP segments in order to allow peripherals to be connected to computers across networks.

intrusion detection system (IDS) Software employed to monitor and detect possible attacks and behaviors that vary from the normal and expected activity. The IDS can be network based, which monitors network traffic, or host based, which monitors activities of a specific system and protects system files and control mechanisms.

intrusion prevention system (IPS) An intrusion detection system (IDS) that is also able to take actions to stop a detected intrusion.

isolation The containment of processes in a system in such a way that they are separated from one another to ensure integrity and confidentiality.

kernel The core of an operating system, a kernel manages the machine’s hardware resources (including the processor and the memory) and provides and controls the way any other software component accesses these resources.

key A discrete data set that controls the operation of a cryptography algorithm. In encryption, a key specifies the particular transformation of plaintext into ciphertext, or vice versa, during decryption. Keys are also used in other cryptographic algorithms, such as digital signature schemes and keyed-hash functions (also known as HMACs), which are often used for authentication and integrity.

keystroke monitoring A type of auditing that can review or record keystrokes entered by a user during an active session.

lattice-based access control model A mathematical model that allows a system to easily represent the different security levels and control access attempts based on those levels. Every pair of elements has a highest lower bound and a lowest upper bound of access rights. The classes stemmed from military designations.

least privilege The security principle that requires each subject to be granted the most restrictive set of privileges needed for the performance of authorized tasks. The application of this principle limits the damage that can result from accident, error, or unauthorized use.

life-cycle assurance Confidence that a trusted system is designed, developed, and maintained with formal designs and controls. This includes design specification and verification, implementation, testing, configuration management, and distribution.

Lightweight Directory Access Protocol (LDAP) A directory service based on a subset of the X.500 standard that allows users and applications to interact with a directory.

link encryption A type of encryption technology that encrypts packets’ headers, trailers, and the data payload. Each network communications node, or hop, must decrypt the packets to read its address and routing information and then re-encrypt the packets. This is different from end-to-end encryption.

logic bomb A malicious program that is triggered by a specific event or condition.

loss potential The potential losses that can be accrued if a threat agent actually exploits a vulnerability.

maintenance hook Instructions within a program’s code that enable the developer or maintainer to enter the program without having to go through the usual access control and authentication processes. Maintenance hooks should be removed from the code before it is released to production; otherwise, they can cause serious security risks. Also called trapdoor or back door.

malware Malicious software. Code written to perform activities that circumvent the security policy of a system. Examples are viruses, malicious applets, Trojan horses, logical bombs, and worms.

mandatory access control (MAC) An access policy that restricts subjects’ access to objects based on the security clearance of the subject and the classification of the object. The system enforces the security policy, and users cannot share their files with other users.

masquerading Impersonating another user, usually with the intention of gaining unauthorized access to a system.

message authentication code (MAC) In cryptography, a message authentication code (MAC) is a generated value used to authenticate a message. A MAC can be generated by HMAC or CBC-MAC methods. The MAC protects both a message’s integrity (by ensuring that a different MAC will be produced if the message has changed) and its authenticity, because only someone who knows the secret key could have modified the message.

multifactor authentication Authentication mechanisms that employ more than one factor. Factors are things a user knows (e.g., password), has (e.g., a hardware token), or is (e.g., biometrics).

multilevel security A class of systems containing information with different classifications. Access decisions are based on the subject’s security clearances, need to know, and formal approval.

Multiprotocol Label Switching (MPLS) A converged data communications protocol designed to improve the routing speed of high-performance networks.

need to know A security principle stating that users should have access only to the information and resources necessary to complete their tasks that fulfill their roles within an organization. Need to know is commonly used in access control criteria by operating systems and applications.

node A system that is connected to a network.

nonrepudiation A service that ensures the sender cannot later falsely deny sending a message or taking an action.

object A passive entity that contains or receives information. Access to an object potentially implies access to the information that it contains. Examples of objects include records, pages, memory segments, files, directories, directory trees, and programs.

object reuse Reassigning to a subject media that previously contained information. Object reuse is a security concern because if insufficient measures were taken to erase the information on the media, the information may be disclosed to unauthorized personnel.

onboarding The process of turning a candidate into a trusted employee who is able to perform all assigned duties.

one-time pad A method of encryption in which the plaintext is combined with a random “pad,” which should be the same length as the plaintext. This encryption process uses a nonrepeating set of random bits that are combined bitwise (XOR) with the message to produce ciphertext. A one-time pad is a perfect encryption scheme because it is unbreakable and each pad is used exactly once, but it is impractical because of all of the required overhead.

operational assurance A level of confidence of a trusted system’s architecture and implementation that enforces the system’s security policy. This can include system architecture, covert channel analysis, system integrity, and trusted recovery.

operational goals Daily goals to be accomplished to ensure the proper operation of an environment.

operator An individual who supports the operations of computer systems—usually a mainframe. The individual may monitor the execution of the system, control the flow of jobs, and develop and schedule batch jobs.

overt channel A path within a computer system or network that is designed for the authorized transfer of data.

password A sequence of characters used to prove one’s identity. It is used during a logon process and should be highly protected.

payment card industry data security standard (PCI DSS) An information security standard for organizations that are involved in payment card transactions.

penetration A successful attempt at circumventing security controls and gaining access to a system.

penetration testing A method of evaluating the security of a computer system or network by simulating an attack that a malicious hacker would carry out. This is done so that vulnerabilities and weaknesses can be uncovered.

permissions The type of authorized interactions that a subject can have with an object. Examples include read, write, execute, add, modify, and delete.

personnel security The procedures that are established to ensure that all personnel who have access to sensitive information have the required authority as well as appropriate clearances. Procedures confirm a person’s background and provide assurance of necessary trustworthiness.

physical controls Controls that pertain to controlling individual access into the facility and different departments, locking systems and removing unnecessary floppy or CD-ROM drives, protecting the perimeter of the facility, monitoring for intrusion, and checking environmental controls.

physical security Controls and procedures put into place to prevent intruders from physically accessing a system or facility. The controls enforce access control and authorized access.

piggyback Unauthorized access to a system by using another user’s legitimate credentials.

plaintext In cryptography, the original readable text before it is encrypted.

playback attack Capturing data and resending the data at a later time in the hope of tricking the receiving system. This is usually carried out to obtain unauthorized access to specific resources.

privacy A security principle that protects an individual’s information and employs controls to ensure that this information is not disseminated or accessed in an unauthorized manner.

procedure Detailed step-by-step instructions to achieve a certain task, which are used by users, IT staff, operations staff, security members, and others.

protection ring An architecture that provides hierarchies of privileged operation modes of a system, which gives certain access rights to processes that are authorized to operate in that mode. Supports the integrity and confidentiality requirements of multitasking operating systems and enables the operating system to protect itself from user programs and rogue processes.

protocol A set of rules and formats that enables the standardized exchange of information between different systems.

pseudo-flaw An apparent loophole deliberately implanted in an operating system or program as a trap for intruders.

public key encryption A type of encryption that uses two mathematically related keys to encrypt and decrypt messages. The private key is known only to the owner, and the public key is available to anyone.

public key infrastructure (PKI) A framework of programs, procedures, communication protocols, and public key cryptography that enables a diverse group of individuals to communicate securely.

purge The removal of sensitive data from a system, storage device, or peripheral device with storage capacity at the end of a processing period. This action is performed in such a way that there is assurance proportional to the sensitivity of the data that the data cannot be reconstructed.

qualitative risk analysis A risk analysis method that uses opinion and experience to judge an organization’s exposure to risks. It uses scenarios and ratings systems. Compare to quantitative risk analysis.

quantitative risk analysis A risk analysis method that attempts to use percentages in damage estimations and assigns real numbers to the costs of countermeasures for particular risks and the amount of damage that could result from the risk. Compare to qualitative risk analysis.

RADIUS (Remote Authentication Dial-in User Service) A security service that authenticates and authorizes dial-up users and is a centralized access control mechanism.

read An operation that results in the flow of information from an object to a subject and does not give the subject the ability to modify the object or the data within the object.

recovery planning The advance planning and preparations that are necessary to minimize loss and to ensure the availability of the critical information systems of an organization after a disruption in service or a disaster.

recovery point objective The acceptable amount of data loss measured in time.

recovery time objective The maximum time period within which a business process must be restored to a designated service level after a disaster to avoid unacceptable consequences.

reference monitor concept An access control concept that refers to an abstract machine that mediates all accesses to objects by subjects. The security kernel enforces the reference monitor concept.

reliability The assurance of a given system, or individual component, performing its mission adequately for a specified period of time under the expected operating conditions.

remote journaling A method of transmitting changes to data to an offsite facility. This takes place as parallel processing of transactions, meaning that changes to the data are saved locally and to an off-site facility. These activities take place in real time and provide redundancy and fault tolerance.

repudiation When the sender of a message denies sending the message. The countermeasure to this is to implement digital signatures.

residual risk The remaining risk after the security controls have been applied. The conceptual formulas that explain the difference between total and residual risk are

threats × vulnerability × asset value = total risk
(threats × vulnerability × asset value) × controls gap = residual risk

risk The likelihood of a threat agent taking advantage of a vulnerability and the resulting business impact. A risk is the loss potential, or probability, that a threat will exploit a vulnerability.

risk analysis A method of identifying risks and assessing the possible damage that could be caused in order to justify security safeguards.

risk management The process of identifying, assessing, and reducing the risk to an acceptable level and implementing the right mechanisms to maintain that level of risk.

role-based access control (RBAC) Type of model that provides access to resources based on the role the user holds within the company or the tasks that the user has been assigned.

rule-based access control (RB-RBAC) Type of model that uses specific rules that indicate what can and cannot happen between a subject and an object. This access control model is built on top of traditional RBAC and is thus commonly called RB-RBAC to disambiguate the otherwise overloaded RBAC acronym.

safeguard A software configuration, hardware, or procedure that eliminates a vulnerability or reduces the risk of a threat agent from being able to exploit a vulnerability. Also called a countermeasure or control.

sandboxing A type of control that isolates processes from the operating system to prevent security violations.

secure configuration management Implementing the set of appropriate procedures to control the life cycle of an application, document the necessary change control activities, and ensure that the changes will not violate the security policy.

Security Assertion Markup Language (SAML) An XML standard that allows the exchange of authentication and authorization data to be shared between security domains.

security evaluation Assesses the degree of trust and assurance that can be placed in systems for the secure handling of sensitive information.

security information and event management (SIEM) A software platform that aggregates security information and security events and presents them in a single, consistent, and cohesive manner.

security kernel The hardware, firmware, and software elements of a trusted computing base (TCB) that implement the reference monitor concept. The kernel must mediate all access between subjects and objects, be protected from modification, and be verifiable as correct.

security label An identifier that represents the security level of an object.

security perimeter An imaginary boundary between the components within the trusted computing base (TCB) and mechanisms that do not fall within the TCB. It is the distinction between trusted and untrusted processes.

security policy Documentation that describes senior management’s directives toward the role that security plays within the organization. It provides a framework within which an organization establishes needed levels of information security to achieve the desired availability, integrity, and confidentiality goals. A policy is a statement of information values, protection responsibilities, and organization commitment managing risks.

security testing Testing all security mechanisms and features within a system to determine the level of protection they provide. Security testing can include penetration testing, formal design and implementation verification, and functional testing.

sensitive information Information that would cause a negative effect on the company if it were lost or compromised.

sensitivity label A piece of information that represents the security level of an object. Sensitivity labels are used by the TCB as the basis for mandatory access control (MAC) decisions.

separation of duties A security principle that splits up a critical task among two or more individuals to ensure that one person cannot complete a risky task by himself.

shoulder surfing When a person looks over another person’s shoulder and watches keystrokes or watches data as it appears on the screen in order to uncover information in an unauthorized manner.

simple security property A Bell-LaPadula security model rule that stipulates that a subject cannot read data at a higher security level.

single loss expectancy (SLE) A dollar amount that is assigned to a single event that represents the company’s potential loss amount if a specific threat were to take place.

asset value × exposure factor = SLE

single sign-on (SSO) A technology that allows a user to authenticate one time and then access resources in the environment without needing to reauthenticate.

social engineering The act of tricking another person into providing confidential information by posing as an individual who is authorized to receive that information.

software-defined networking (SDN) An approach to networking that relies on distributed software to provide improved agility and efficiency by centralizing the configuration and control of networking devices.

spoofing Presenting false information, usually within packets, to trick other systems and hide the origin of the message. This is usually done by hackers so that their identity cannot be successfully uncovered.

standards Rules indicating how hardware and software should be implemented, used, and maintained. Standards provide a means to ensure that specific technologies, applications, parameters, and procedures are carried out in a uniform way across the organization. They are compulsory.

star property (*-property) A Bell-LaPadula security model rule that stipulates that a subject cannot write data to an object at a lower security level.

strategic goals Long-term goals that are broad, general statements of intent. Operational and tactical goals support strategic goals and all are a part of a planning horizon.

subject An active entity, generally in the form of a person, process, or device, that causes information to flow among objects or that changes the system state.

supervisor state One of several states in which an operating system may operate, and the only one in which privileged instructions may be executed by the CPU.

supervisory control and data acquisition (SCADA) A system for remotely monitoring and controlling physical systems such as power and manufacturing plants.

synthetic transaction A transaction that is executed in real time by a software agent to test or monitor the performance of a distributed system.

tabletop exercise (TTX) A type of exercise in which participants respond to notional events to test out procedures and ensure they actually do what they’re intended to and that everyone knows their role in responding to the events.

TACACS (Terminal Access Controller Access Control System) A client/server authentication protocol that provides the same type of functionality as RADIUS and is used as a central access control mechanism mainly for remote users.

tactical goals Midterm goals to accomplish. These may be milestones to accomplish within a project or specific projects to accomplish in a year. Strategic, tactical, and operational goals make up a planning horizon.

technical controls These controls, also called logical access control mechanisms, work in software to provide availability, integrity, or confidentiality protection. Some examples are passwords, identification and authentication methods, security devices, auditing, and the configuration of the network.

Tempest The study and control of spurious electronic signals emitted by electrical equipment. Tempest equipment is implemented to prevent intruders from picking up information through the airwaves with listening devices.

threat Any potential danger that a vulnerability will be exploited by a threat agent.

top-down approach An approach in which the initiation, support, and direction for a project come from top management and work their way down through middle management and then to staff members.

topology The physical construction of how nodes are connected to form a network.

total risk When a safeguard is not implemented, an organization is faced with the total risk of that particular vulnerability.

trademark A legal right that protects a word, name, product shape, symbol, color, or a combination of these used to identify a product or a company.

Trojan horse A computer program that has an apparently or actually useful function, but that also contains hidden malicious capabilities to exploit a vulnerability and/or provide unauthorized access into a system.

trusted computer system A system that has the necessary controls to ensure the security policy will not be compromised and that can process a range of sensitive or classified information simultaneously.

trusted computing base (TCB) All of the protection mechanisms within a computer system (software, hardware, and firmware) that are responsible for enforcing a security policy.

trusted path A mechanism within the system that enables the user to communicate directly with the TCB. This mechanism can be activated only by the user or the TCB and not by an untrusted mechanism or process.

trusted recovery A set of procedures that restores a system and its data in a trusted manner after the system has been disrupted or a system failure has occurred.

user A person or process that is accessing a computer system.

user ID A unique set of characters or code that is used to identify a specific user to a system.

validation The act of performing tests and evaluations to test a system’s security level to see if it complies with security specifications and requirements.

virus A small application, or string of code, that infects applications. The main function of a virus is to reproduce, and it requires a host application to do this. It can damage data directly or degrade system performance.

vulnerability The absence or weakness of a safeguard that could be exploited.

war dialing An attack in which a long list of phone numbers is inserted into a war-dialing program in the hope of finding a modem that can be exploited to gain unauthorized access.

whitelist A set of known good resources such as IP addresses, domain names, or applications.

work factor The estimated time and effort required for an attacker to overcome a security control.

worm An independent program that can reproduce by copying itself from one system to another. It may damage data directly or degrade system performance by tying up resources.

write An operation that results in the flow of information from a subject to an object.