Cybersecurity Fundamentals – Terms

Acceptable interruption window

The maximum period of time that a system can be unavailable before compromising the achievement of the enterprise’s business objectives.

Acceptable use policy

A policy that establishes an agreement between users and the enterprise and defines for all parties’ the ranges of use that are approved before gaining access to a network or the Internet.

Access control list (ACL)

An internal computerized table of access rules regarding the levels of computer access permitted to logon IDs and computer terminals. Also referred to as access control tables.

Access path

The logical route that an end user takes to access computerized information. Typically includes a route through the operating system, telecommunications software, selected application software and the access control system.

Access rights

The permission or privileges granted to users, programs or workstations to create, change, delete or view data and files within a system, as defined by rules established by data owners and the information security policy.

Accountability

The ability to map a given activity or event back to the responsible party.

Advanced Encryption Standard (AES)

A public algorithm that supports keys from 128 bits to 256 bits in size.

Advanced persistent threat (APT)

An adversary that possesses sophisticated levels of expertise and significant resources which allow it to create opportunities to achieve its objectives using multiple attack vectors (NIST SP800-61).

Adversary

A threat agent.

Adware

A software package that automatically plays, displays or downloads advertising material to a computer after the software is installed on it or while the application is being used. In most cases, this is done without any notification to the user or without the user’s consent and may also refer to software that displays advertisements.

Alert situation

The point in an emergency procedure when the elapsed time passes a threshold and the interruption is not resolved and initiates a series of escalation steps.

Alternate facilities

Locations and infrastructures from which emergency or backup processes are executed, when the main premises are unavailable or destroyed; includes other buildings, offices or data processing centers.

Alternate process

Automatic or manual process designed and established to continue critical business processes from point-of-failure to return-to-normal.

Analog

A transmission signal that varies continuously in amplitude and time and is generated in wave formation. Analog signals are used in telecommunications.

Anti-malware

A technology widely used to prevent, detect and remove many categories of malware, including computer viruses, worms, Trojans, keyloggers, malicious browser plug-ins, adware and spyware.

Antivirus software

An application software deployed at multiple points in an IT architecture. It is designed to detect and potentially eliminate virus code before damage is done and repair or quarantine files that have already been infected.

Application layer

In the Open Systems Interconnection (OSI) communications model, provides services for an application program to ensure that effective communication with another application program in a network is possible.

Architecture

Description of the fundamental underlying design of the components of the business system, or of one element of the business system (e.g., technology), the relationships among them, and the manner in which they support enterprise objectives.

Asset

Something of either tangible or intangible value that is worth protecting, including people, information, infrastructure, finances and reputation.

Asymmetric key (public key)

A cipher technique in which different cryptographic keys are used to encrypt and decrypt a message. See public key encryption.

Attack

An actual occurrence of an adverse event.

Attack mechanism

A method used to deliver the exploit. Unless the attacker is personally performing the attack it may involve a payload, or container, that delivers the exploit to the target.

Attack vector

A path or route used by the adversary to gain access to the target (asset). There are two types: ingress and egress (also known as data exfiltration).

Audit trail

A visible trail of evidence enabling one to trace information contained in statements or reports back to the original input source.

Authentication

The act of verifying the identity of a user and the user’s eligibility to access computerized information and also designed to protect against fraudulent logon activity. It can also refer to the verification of the correctness of a piece of data.

Authenticity

Undisputed authorship.

Availability

Ensuring timely and reliable access to and use of information.

Back door

A means of regaining access to a compromised system by installing software or configuring existing software to enable remote access under attacker-defined conditions.

Bandwidth

The range between the highest and lowest transmittable frequencies. It equates to the transmission capacity of an electronic line and is expressed in bytes per second or Hertz (cycles per second).

Bastion

System heavily fortified against attacks.

Biometrics

A security technique that verifies an individual’s identity by analyzing a unique physical attribute, such as a handprint.

Block cipher

A public algorithm that operates on plaintext in blocks (strings or groups) of bits.

Botnet

A term derived from "robot network;" is a large automated and distributed network of previously compromised computers that can be simultaneously controlled to launch large-scale attacks such as a denial-of-service attack on selected victims.

Boundary

Logical and physical controls to define a perimeter between the organization and the outside world.

Bridges

Data link layer devices developed in the early 1980s to connect local area networks (LANs) or create two separate LAN or wide area network (WAN) network segments from a single segment to reduce collision domains. They act as store-and-forward devices in moving frames toward their destination.

Bring your own device (BYOD)

An enterprise policy used to permit partial or full integration of user-owned mobile devices for business purposes.

Broadcast

A method to distribute information to multiple recipients simultaneously.

Brute force

A class of algorithms that repeatedly try all possible combinations until a solution is found.

Brute force attack

Repeatedly trying all possible combinations of passwords or encryption keys until the correct one is found.

Buffer overflow

Occurs when a program or process tries to store more data in a buffer (temporary data storage area) than it was intended to hold corrupting or overwriting the valid data held in them.

Business continuity plan (BCP)

A plan used by an enterprise to respond to disruption of critical business processes. Depends on the contingency plan for restoration of critical systems.

Business impact analysis/assessment (BIA)

Evaluating the criticality and sensitivity of information assets. An exercise that determines the impact of losing the support of any resource to an enterprise, establishes the escalation of that loss over time, identifies the minimum resources needed to recover, and prioritizes the recovery of processes and the supporting system.

Certificate (Certification) authority (CA)

A trusted third party that serves authentication infrastructures or enterprises and registers entities and issues them certificates.

Certificate revocation list (CRL)

An instrument for checking the continued validity of the certificates for which the certification authority (CA) has responsibility. Provides digital certificates that are no longer valid. The time gap between two updates is very critical and is also a risk in digital certificates verification.

Chain of custody

A legal principle regarding the validity and integrity of evidence. It requires accountability for anything that will be used as evidence in a legal proceeding to ensure that it can be accounted for from the time it was collected until the time it is presented in a court of law. Includes documentation.

Checksum

A mathematical value that is assigned to a file and used to "test" the file at a later date to verify that the data contained in the file has not been maliciously changed.

Chief Information Security Officer (CISO)

The person in charge of information security within the enterprise.

Chief Security Officer (CSO)

The person usually responsible for all security matters both physical and digital in an enterprise.

Cipher

An algorithm to perform encryption.

Ciphertext

Information generated by an encryption algorithm to protect the plaintext and that is unintelligible to the unauthorized reader.

Cleartext

Data that is not encrypted. Also known as plaintext.

Cloud computing

Convenient, on-demand network access to a shared pool of resources that can be rapidly provisioned and released with minimal management effort or service provider interaction.

Collision

The situation that occurs when two or more demands are made simultaneously on equipment that can handle only one at any given instant (Federal Standard 1037C).

Common Attack Pattern Enumeration and Classification (CAPEC)

A catalogue of attack patterns as "an abstraction mechanism for helping describe how an attack against vulnerable systems or networks is executed" published by the MITRE Corporation.

Compartmentalization

A process for protecting very high value assets or in environments where trust is an issue. Access to an asset requires two or more processes, controls or individuals.

Compliance

Adherence to, and the ability to demonstrate adherence to, mandated requirements defined by laws and regulations, as well as voluntary requirements resulting from contractual obligations and internal policies.

Compliance documents

Policies, standard and procedures that document the actions that are required or prohibited. Violations may be subject to disciplinary actions.

Computer emergency response team (CERT)

A group of people integrated at the enterprise with clear lines of reporting and responsibilities for standby support in case of an information systems emergency. This group will act as an efficient corrective control, and should also act as a single point of contact for all incidents and issues related to information systems.

Computer forensics

The application of the scientific method to digital media to establish factual information for judicial review. This process often involves investigating computer systems to determine whether they are or have been used for illegal or unauthorized activities.

Confidentiality

Preserving authorized restrictions on access and disclosure, including means for protecting privacy and proprietary information.

Configuration management

The control of changes to a set of configuration items over a system life cycle.

Consumerization

A new model in which emerging technologies are first embraced by the consumer market and later spread to the business.

Containment

Actions taken to limit exposure after an incident has been identified and confirmed.

Content filtering

Controlling access to a network by analyzing the contents of the incoming and outgoing packets and either letting them pass or denying them based on a list of rules. Differs from packet filtering.

Control

The means of managing risk, including policies, procedures, guidelines, practices or organizational structures, which can be of an administrative, technical, management, or legal nature. Also used as a synonym for safeguard or countermeasure.

Countermeasure

Any process that directly reduces a threat or vulnerability.

Critical infrastructure

Systems whose incapacity or destruction would have a debilitating effect on the economic security of an enterprise, community or nation.

Criticality

The importance of a particular asset or function to the enterprise, and the impact if that asset or function is not available.

Criticality analysis

An analysis to evaluate resources or business functions to identify their importance to the enterprise, and the impact if a function cannot be completed or a resource is not available.

Cross-site scripting (XSS)

A type of injection, in which malicious scripts are injected into otherwise benign and trusted web sites and can occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user.

Cryptography

The art of designing, analyzing and attacking cryptographic schemes.

Cryptosystem

A pair of algorithms that take a key and convert plaintext to ciphertext and back.

Cybercop

An investigator of activities related to computer crime.

Cyberespionage

Activities conducted in the name of security, business, politics or technology to find information that ought to remain secret. It is not inherently military.

Cybersecurity

The protection of information assets by addressing threats to information processed, stored, and transported by internetworked information systems.

Cybersecurity architecture

Describes the structure, components and topology (connections and layout) of security controls within an enterprise’s IT infrastructure. The security architecture shows how defense in depth is implemented and how layers of control are linked and is essential to designing and implementing security controls

Cyberwarfare

Activities supported by military organizations with the purpose to threat the survival and well-being of society/foreign entity.

Data classification

The assignment of a level of sensitivity to data (or information) that results in the specification of controls for each level of classification. Levels of sensitivity of data are assigned according to predefined categories as data are created, amended, enhanced, stored or transmitted.

Data custodian

The individual(s) and department(s) responsible for the storage and safeguarding of computerized data.

Data Encryption Standard (DES)

An algorithm for encoding binary data. It is a secret key cryptosystem published by the National Bureau of Standards (NBS), the predecessor of the US National Institute of Standards and Technology (NIST) but has been replaced by the Advanced Encryption Standard (AES).

Data leakage

Siphoning out or leaking information by dumping computer files or stealing computer reports and tapes.

Data owner

The individual(s), normally a manager or director, who has responsibility for the integrity, accurate reporting and use of computerized data.

Data retention

Refers to the policies that govern data and records management for meeting internal, legal and regulatory data archival requirements.

Database

A stored collection of related data needed by enterprises and individuals to meet their information processing and retrieval requirements.

Decentralization

The process of distributing computer processing to different locations within an enterprise.

Decryption

A technique used to recover the original plaintext from the ciphertext so that it is intelligible to the reader and a reverse process of the encryption.

Decryption key

A digital piece of information used to recover plaintext from the corresponding ciphertext by decryption.

Defense in depth

The practice of layering defenses to provide added protection. Increases security by raising the effort needed in an attack. This strategy places multiple barriers between an attacker and an enterprise’s computing and information resources.

Demilitarized zone (DMZ)

A screened (firewalled) network segment that acts as a buffer zone between a trusted and untrusted network. Typically used to house systems such as web servers that must be accessible from both internal networks and the Internet.

Denial 0f Service Attack

An assault on a service from a single source that floods it with so many requests that it becomes overwhelmed and is either stopped completely or operates at a significantly reduced rate.

Digital certificate

A piece of information, a digitized form of signature, that provides sender authenticity, message integrity and nonrepudiation and generated using the sender’s private key or applying a one-way hash function.

Digital forensics

The process of identifying, preserving, analyzing and presenting digital evidence in a manner that is legally acceptable in any legal proceedings.

Digital signature

A piece of information, a digitized form of signature, that provides sender authenticity, message integrity and nonrepudiation and is generated using the sender’s private key or applying a one-way hash function.

Disaster

A sudden, unplanned calamitous event causing great damage or loss. Any event that creates an inability on an organization’s part to provide critical business functions for some predetermined period of time. Similar terms are business interruption, outage and catastrophe.

Disaster recovery plan (DRP)

A set of human, physical, technical and procedural resources to recover, within a defined time and cost, an activity interrupted by an emergency or disaster.

Discretionary access control (DAC)

A means of restricting access to objects based on the identity of subjects and/or groups to which they belong. The controls are discretionary in the sense that a subject with a certain access permission is capable of passing that permission (perhaps indirectly) on to any other subject.

Domain name system (DNS)

A hierarchical database that is distributed across the Internet that allows names to be resolved into IP addresses (and vice versa) to locate services such as web and email servers.

Domain name system (DNS) exfiltration

Tunneling over DNS to gain network access. Lower-level attack vector for simple to complex data transmission, slow but difficult to detect.

Due care

The level of care expected from a reasonable person of similar competency under similar conditions.

Due diligence

The performance of those actions that are generally regarded as prudent, responsible and necessary to conduct a thorough and objective investigation, review and/or analysis.

Dynamic ports

49152 through 65535: Not listed by IANA because of their dynamic nature.

Eavesdropping

Listening a private communication without permission.

Ecommerce

The processes by which enterprises conduct business electronically with their customers, suppliers and other external business partners, using the Internet as an enabling technology.

Egress

Network communications going out.

Elliptical curve cryptography (ECC)

An algorithm that combines plane geometry with algebra to achieve stronger authentication with smaller keys compared to traditional methods, such as RSA, which primarily use algebraic factoring. Smaller keys are more suitable to mobile devices.

Encapsulation security payload (ESP)

Protocol, which is designed to provide a mix of security services in IPv4 and IPv6. ESP can be used to provide confidentiality, data origin authentication, connectionless integrity, an anti-replay service (a form of partial sequence integrity), and (limited) traffic flow confidentiality (RFC 4303).

Encryption

The process of taking an unencrypted message (plaintext), applying a mathematical function to it (encryption algorithm with a key) and producing an encrypted message (ciphertext).

Encryption algorithm

A mathematically based function or calculation that encrypts/decrypts data.

Encryption key

A piece of information, in a digitized form, used by an encryption algorithm to convert the plaintext to the ciphertext.

Eradication

restoring backups to achieve a clean state of the system, removing the root cause, improving defenses and performing vulnerability analysis to find further potential damage from the same root cause.

Ethernet

A popular network protocol and cabling scheme that uses a bus topology and carrier sense multiple access/collision detection (CSMA/CD) to prevent network failures or collisions when two devices try to access the network at the same time.

Event

Something that happens at a specific place and/or time.

Evidence

Information that proves or disproves a stated issue. Information that an auditor gathers in the course of performing an IS audit; relevant if it pertains to the audit objectives and has a logical relationship to the findings and conclusions it is used to support.

Exploit

Full use of a vulnerability for the benefit of an attacker.

File transfer protocol (FTP)

A protocol used to transfer files over a Transmission Control Protocol/ Internet Protocol (TCP/IP) network (Internet, UNIX, etc.).

Firewall

A system or combination of systems that enforces a boundary between two or more networks, typically forming a barrier between a secure and an open environment such as the Internet.

Forensic examination

The process of collecting, assessing, classifying and documenting digital evidence to assist in the identification of an offender and the method of compromise.

Freeware

Software available free of charge

Gateway

A device (router, firewall) on a network that serves as an entrance to another network.

Governance

Ensures that stakeholder needs, conditions and options are evaluated to determine balanced, agreed-on enterprise objectives to be achieved; setting direction through prioritization and decision making; and monitoring performance and compliance against agreed-on direction and objectives.

Governance, Risk Management and Compliance (GRC)

A business term used to group the three close-related disciplines responsible for the protection of assets and operations.

Guideline

A description of a particular way of accomplishing something that is less prescriptive than a procedure.

Hacker

An individual who attempts to gain unauthorized access to a computer system.

Hash function

An algorithm that maps or translates one set of bits into another (generally smaller) so that a message yields the same result every time the algorithm is executed using the same message as input.

Hash total

The total of any numeric data field in a document or computer file. This total is checked against a control total of the same field to facilitate accuracy of processing.

Hashing

Using a hash function (algorithm) to create hash valued or checksums that validate message integrity.

Hijacking

An exploitation of a valid network session for unauthorized purposes.

Honeypot

A specially configured server, also known as a decoy server, designed to attract and monitor intruders in a manner such that their actions do not affect production systems. Also known as "decoy server."

Horizontal defense in depth

Controls are placed in various places in the path to access an asset.

Hubs

A common connection point for devices in a network, are used to connect segments of a local area network (LAN) and contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Human firewall

A person prepared to act as a network layer of defense through education and awareness.

Hypertext Transfer Protocol (HTTP)

A communication protocol used to connect to servers on the World Wide Web. Its primary function is to establish a connection with a web server and transmit hypertext markup language (HTML), extensible markup language (XML) or other pages to client browsers.

IEEE (Institute of Electrical and Electronics Engineers)

Pronounced I-triple-E; an organization composed of engineers, scientists and students. Best known for developing standards for the computer and electronics industry.

IEEE 802.11

A family of specifications developed by the Institute of Electrical and Electronics Engineers (IEEE) for wireless local area network (WLAN) technology. 802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients.

Imaging

A process that allows one to obtain a bit-for-bit copy of data to avoid damage of original data or information when multiple analyses may be performed and made to obtain residual data, such as deleted files, fragments of deleted files and other information present, from the disk for analysis.

Impact

Magnitude of loss resulting from a threat exploiting a vulnerability.

Impact analysis

A study to prioritize the criticality of information resources for the enterprise based on costs (or consequences) of adverse events and threats to assets are identified and potential business losses determined for different time periods.

Incident

Any event that is not part of the standard operation of a service and that causes, or may cause, an interruption to, or a reduction in, the quality of that service.

Incident response

The response of an enterprise to a disaster or other significant event that may significantly affect the enterprise, its people, or its ability to function productively and may include evacuation of a facility, initiating a disaster recovery plan (DRP), performing damage assessment.

Incident response plan

The operational component of incident management and includes documented procedures and guidelines for defining the criticality of incidents, reporting and escalation process, and recovery procedures.

Information security

Ensures that within the enterprise, information is protected against disclosure to unauthorized users (confidentiality), improper modification (integrity), and nonaccess when required (availability).

Information security program

The overall combination of technical, operational and procedural measures and management structures implemented to provide for the confidentiality, integrity and availability of information based on business requirements and risk analysis.

Information systems (IS)

Strategic, managerial and operational activities involved in gathering, processing, storing, distributing and using information and its related technologies. Information systems are distinct from information technology (IT) in that an information system has an IT component that interacts with the process components.

Infrastructure as a Service (IaaS)

Offers the capability to provision processing, storage, networks and other fundamental computing resources, enabling the customer to deploy and run arbitrary software, which can include operating systems (OSs) and applications.

Ingestion

A process to convert information extracted to a format that can be understood by investigators. See also Normalization.

Ingress

Network communications coming in.

Inherent risk

The risk level or exposure without taking into account the actions that management has taken or might take (e.g., implementing controls).

Injection

A general term for attack types which consist of injecting code that is then interpreted/ executed by the application (OWASP).

Intangible asset

An asset that is not physical in nature. Examples include: intellectual property (patents, trademarks, copyrights, processes), goodwill and brand recognition.

Integrity

The guarding against improper information modification or destruction, and includes ensuring information nonrepudiation and authenticity.

Intellectual property

Intangible assets that belong to an enterprise for its exclusive use. Examples include: patents, copyrights, trademarks, ideas, and trade secrets.

International Standards Organization (ISO)

The world’s largest developer of voluntary International Standards.

Internet Assigned Numbers Authority (IANA)

Responsible for the global coordination of the DNS root, IP addressing, and other Internet protocol resources.

Internet Control Message Protocol (ICMP)

A set of protocols that allow systems to communicate information about the state of services on other systems and used in determining whether systems are up, maximum packet sizes on links, whether a destination host/network/port is available.

Internet protocol (IP)

Specifies the format of packets and the addressing scheme.

Internet protocol (IP) packet spoofing

An attack using packets with the spoofed source Internet packet (IP) addresses. This technique exploits applications that use authentication based on IP addresses. This technique also may enable an unauthorized user to gain root access on the target system.

Internet service provider (ISP)

A third party that provides individuals and enterprises with access to the Internet and a variety of other Internet-related services.

Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX)

IPX is layer 3 of the open systems interconnect (OSI) model network protocol; SPX is layer 4 transport protocol. The SPX layer sits on top of the IPX layer and provides connection-oriented services between two nodes on the network.

Interrogation

Used to obtain prior indicators or relationships, including telephone numbers, IP addresses and names of individuals, from extracted data.

Intruder

Individual or group gaining access to the network and its resources without permission.

Intrusion detection

The process of monitoring the events occurring in a computer system or network to detect signs of unauthorized access or attack.

Intrusion detection system (IDS)

Inspects network and host security activity to identify suspicious patterns that may indicate a network or system attack.

Intrusion Prevention

A preemptive approach to network security used to identify potential threats and respond to them to stop, or at least limit, damage or disruption.

Intrusion prevention system (IPS)

A system designed to not only detect attacks, but also to prevent the intended victim hosts from being affected by the attacks.

Investigation

The collection and analysis of evidence with the goal to identifying the perpetrator of an attack or unauthorized use or access.

IP address

A unique binary number used to identify devices on a TCP/IP network.

IP Authentication Header (AH)

Protocol used to provide connectionless integrity and data origin authentication for IP datagrams (hereafter referred to as just "integrity") and to provide protection against replays. (RFC 4302). Ensures data integrity with a checksum that a message authentication code, such as MD5, generates.

IP Security (IPSec)

A set of protocols developed by the Internet Engineering Task Force (IETF) to support the secure exchange of packets.

IT governance

The responsibility of executives and the board of directors; consists of the leadership, organizational structures and processes that ensure that the enterprise’s IT sustains and extends the enterprise’s strategies and objectives.

Kernel mode

Used for execution of privileged instructions for the internal operation of the system. There are no protections from errors or malicious activity and all parts of the system and memory are accessible.

Key length

The size of the encryption key measured in bits.

Key risk indicator (KRI)

A subset of risk indicators that are highly relevant and possess a high probability of predicting or indicating important risk. See also Risk Indicator.

Keylogger

Software used to record all keystrokes on a computer.

Latency

The time it takes a system and network delay to respond. More specifically, its the time a system takes to retrieve data and is the time it takes for a packet to travel from source to the final destination.

Layer 2 switches

Data link level devices that can divide and interconnect network segments and help to reduce collision domains in Ethernet-based networks.

Layer 3 and 4 switches

Switches with operating capabilities at layer 3 and layer 4 of the open systems interconnect (OSI) model. They look at the incoming packet’s networking protocol, e.g., IP, and then compare the destination IP address to the list of addresses in their tables, to actively calculate the best way to send a packet to its destination.

Layer 4 to 7 switches

Used for load balancing among groups of servers. Also known as content-switches, content services switches, web-switches or application-switches.

Legacy system

Outdated computer systems.

Likelihood

The probability of something happening.

Local area network (LAN)

Communication network that serves several users within a specified geographic area and functions as a distributed processing system in which each computer in the network does its own processing and manages some of its data.

Log

To record details of information or events in an organized record-keeping system, usually sequenced in the order in which they occurred.

Logical access

Ability to interact with computer resources granted using identification, authentication and authorization.

Logical access controls

The policies, procedures, organizational structure and electronic access controls designed to restrict access to computer software and data files.

Media access control (MAC) address

A unique identifier assigned to network interfaces for communications on the physical network segment.

MAC header

Represents the hardware address of an network interface controller (NIC) inside a data packet.

Mail relay server

An electronic mail (email) server that relays messages so that neither the sender nor the recipient is a local user.

Mainframe

A large high-speed computer, especially one supporting numerous workstations or peripherals.

Malware

Short for malicious software. Designed to infiltrate, damage or obtain information from a computer system without the owner’s consent and commonly taken to include computer viruses, worms, Trojan horses, spyware and adware.

Mandatory access control (MAC)

A means of restricting access to data based on varying degrees of security requirements for information contained in the objects and the corresponding security clearance of users or programs acting on their behalf.

Man in the middle attack

An attack strategy in which the attacker intercepts the communication stream between two parts of the victim system and then replaces the traffic between the two components with the intruder’s own, eventually assuming control of the communication.

Masking

A computerized technique of blocking out the display of sensitive information, such as passwords, on a computer terminal or report.

Message authentication code

An American National Standards Institute (ANSI) standard checksum that is computed using Data Encryption Standard (DES).

Message digest

A smaller extrapolated version of the original message created using a message digest algorithm.

Message digest algorithm

SHA1, MD2, MD4 and MD5. These algorithms are one-way functions unlike private and public key encryption algorithms. All algorithms take a message of arbitrary length and produce a 128-bit message digest.

Metropolitan area network (MAN)

A data network intended to serve an area the size of a large city.

Miniature fragment attack

Using this method, an attacker fragments the IP packet into smaller ones and pushes it through the firewall, in the hope that only the first of the sequence of fragmented packets would be examined and the others would pass without review.

Mirrored site

An alternate site that contains the same information as the original and are set up for backup and disaster recovery and to balance the traffic load for numerous download requests. Such download mirrors are often placed in different locations throughout the Internet.

Mobile device

A small, handheld computing devices, typically having a display screen with touch input and/or a miniature keyboard and weighing less than two pounds.

Mobile site

The use of a mobile/temporary facility to serve as a business resumption location. The facility can usually be delivered to any site and can house information technology and staff.

Monitoring policy

Rules outlining or delineating the way in which information about the use of computers, networks, applications and information is captured and interpreted.

Multifactor authentication

A combination of more than one authentication method, such as token and password (or personal identification number [PIN] or token and biometric device).

National Institute for Standards and Technology (NIST)

Develops tests, test methods, reference data, proof-of concept implementations, and technical analyses to advance the development and productive use of information technology. A US government entity that creates mandatory standards that are followed by federal agencies and those doing business with them.

Network basic input/output system (NetBIOS)

A program that allows applications on different computers to communicate within a local area network (LAN).

Network address translation (NAT)

A methodology of modifying network address information in datagram packet headers while they are in transit across a traffic routing device for the purpose of remapping one IP address space into another.

Network interface card (NIC)

A communication card that when inserted into a computer, allows it to communicate with other computers on a network. Most are designed for a particular type of network or protocol.

Network news transfer protocol (NNTP)

Used for the distribution, inquiry, retrieval, and posting of Netnews articles using a reliable stream-based mechanism. For news-reading clients, it enables retrieval of news articles that are stored in a central database, giving subscribers the ability to select only those articles they wish to read (RFC 3977).

Network segmentation

A common technique to implement network security is to segment an organization’s network into separate zones that can be separately controlled, monitored and protected.

Network traffic analysis

Identifies patterns in network communications. Traffic analysis does not need to have the actual content of the communication but analyzes where traffic is taking place, when and for how long communications occur and the size of information transferred.

Nonintrusive monitoring

The use of transported probes or traces to assemble information, track traffic and identify vulnerabilities.

Nonrepudiation

The assurance that a party cannot later deny originating data; provision of proof of the integrity and origin of the data and that can be verified by a third party. A digital signature can provide nonrepudiation.

Normalization

The elimination of redundant data.

Obfuscation

The deliberate act of creating source or machine code that is difficult for humans to understand.

Open Systems Interconnect (OSI) model

A model for the design of a network and defines groups of functionality required to network computers into layers. Each layer implements a standard protocol to implement its functionality. There are seven layers to this model.

Operating system (OS)

A master control program that runs the computer and acts as a scheduler and traffic controller.

Open Web Application Security Project (OWASP)

An open community dedicated to enabling organizations to conceive, develop, acquire, operate, and maintain applications that can be trusted.

Outcome measure

Represents the consequences of actions previously taken; often referred to as a lag indicator. Frequently focuses on results at the end of a time period and characterize historic performance. They are also referred to as a key goal indicator (KGI) and used to indicate whether goals have been met.

Outsourcing

A formal agreement with a third party to perform IS or other business functions for an enterprise.

Packet

Data unit that is routed from source to destination in a packet-switched network. Contains both routing information and data. Transmission Control Protocol/Internet Protocol (TCP/IP) is such a packet-switched network.

Packet filtering

Controlling access to a network by analyzing the attributes of the incoming and outgoing packets and either letting them pass, or denying them, based on a list of rules.

Packet switching

The process of transmitting messages in convenient pieces that can be reassembled at the destination.

Passive response

A response option in intrusion detection in which the system simply reports and records the problem detected, relying on the user to take subsequent action.

Password

A protected, generally computer-encrypted string of characters that authenticate a computer user to the computer system.

Password cracker

A tool that tests the strength of user passwords by searching for passwords that are easy to guess. It repeatedly tries words from specially crafted dictionaries and often also generates thousands (and in some cases, even millions) of permutations of characters, numbers and symbols.

Patch

Fixes to software programming errors and vulnerabilities.

Patch management

An area of systems management that involves acquiring, testing and installing multiple patches (code changes) to an administered computer system in order to maintain up-to-date software and often to address security risk.

Payload

The section of fundamental data in a transmission. In malicious software this refers to the section containing the harmful data/code.

Penetration testing

A live test of the effectiveness of security defenses through mimicking the actions of real-life attackers.

Personal identification number (PIN)

A type of password (i.e., a secret number assigned to an individual) that, in conjunction with some means of identifying the individual, serves to verify the authenticity of the individual.

Phishing

This is a type of electronic mail (email) attack that attempts to convince a user that the originator is genuine, but with the intention of obtaining information for use in social engineering.

Plain old telephone service (POTS)

A wired telecommunications system.

Platform as a Service (PaaS)

Offers the capability to deploy onto the cloud infrastructure customer-created or -acquired applications that are created using programming languages and tools supported by the provider.

Policy

Generally, a document that records a high-level principle or course of action that has been decided on. The intended purpose is to influence and guide both present and future decision making to be in line with the philosophy, objectives and strategic plans established by the enterprise’s management teams.

Port (Port number)

A process or application-specific software element serving as a communication end point for the Transport Layer IP protocols (UDP and TCP).

Port scanning

The act of probing a system to identify open ports.

Prime number

A natural number greater than 1 that can only be divided by 1 and itself.

Principle of least privilege/access

Controls used to allow the least privilege access needed to complete a task.

Privacy

Freedom from unauthorized intrusion or disclosure of information about an individual.

Probe

Inspect a network or system to find weak spots.

Procedure

A document containing a detailed description of the steps necessary to perform specific operations in conformance with applicable standards. Defined as part of processes.

Protocol

The rules by which a network operates and controls the flow and priority of transmissions.

Proxy server

A server that acts on behalf of a user. Accept a connection from a user, make a decision as to whether the user or client IP address is permitted to use it, perhaps perform additional authentication, and complete a connection to a remote destination on behalf of the user.

Public key encryption

A cryptographic system that uses two keys: one is a public key, which is known to everyone, and the second is a private or secret key, which is only known to the recipient of the message. See also Asymmetric Key.

Public key infrastructure (PKI)

A series of processes and technologies for the association of cryptographic keys with the entity to whom those keys were issued.

Public switched telephone network (PSTN)

A communications system that sets up a dedicated channel (or circuit) between two points for the duration of the transmission.

Ransomware

Malware that restricts access to the compromised systems until a ransom demand is satisfied.

Reciprocal agreement

Emergency processing agreement between two or more enterprises with similar equipment or applications. Typically, participants of this promise to provide processing time to each other when an emergency arises.

Recovery

The phase in the incident response plan that ensures that affected systems or services are restored to a condition specified in the service delivery objectives (SDOs) or business continuity plan (BCP).

Recovery action

Execution of a response or task according to a written procedure.

Recovery point objective (RPO)

Determined based on the acceptable data loss in case of a disruption of operations. It indicates the earliest point in time that is acceptable to recover the data. Effectively quantifies the permissible amount of data loss in case of interruption.

Recovery time objective (RTO)

The amount of time allowed for the recovery of a business function or resource after a disaster occurs.

Redundant site

A recovery strategy involving the duplication of key IT components, including data or other key business processes, whereby fast recovery can take place.

Registered ports

1024 through 49151: Listed by the IANA and on most systems can be used by ordinary user processes or programs executed by ordinary users.

Registration authority (RA)

The individual institution that validates an entity’s proof of identity and ownership of a key pair.

Regulation

Rules or laws defined and enforced by an authority to regulate conduct.

Regulatory requirements

Rules or laws that regulate conduct and that the enterprise must obey to become compliant.

Remediation

After vulnerabilities are identified and assessed, appropriate remediation can take place to mitigate or eliminate the vulnerability.

Remote access (RAS)

Refers to any combination of hardware and software to enable the remote access to tools or information that typically reside on a network of IT devices.

Removable media

Any type of storage device that can be removed from the system while is running.

Repeaters

A physical layer device that regenerates and propagates electrical signals between two network segments. They receive signals from one network segment and amplify (regenerate) the signal to compensate for signals (analog or digital) distorted by transmission loss due to reduction of signal strength during transmission

Replay

The ability to copy a message or stream of messages between two parties and replay (retransmit) them to one or more of the parties.

Residual risk

The remaining risk after management has implemented a risk response.

Resilience

The ability of a system or network to resist failure or to recover quickly from any disruption, usually with minimal recognizable effect.

Return on investment (ROI)

A measure of operating performance and efficiency, computed in its simplest form by dividing net income by the total investment over the period being considered.

Return oriented attacks

An exploit technique in which the attacker uses control of the call stack to indirectly execute cherry-picked machine instructions immediately prior to the return instruction in subroutines within the existing program code.

Risk

The combination of the probability of an event and its consequence (ISO/IEC 73).

Risk acceptance

If the risk is within the enterprise’s risk tolerance or if the cost of otherwise mitigating the risk is higher than the potential loss, the enterprise can assume the risk and absorb any losses.

Risk assessment

A process used to identify and evaluate risk and its potential effects. Used to identify those items or areas that present the highest risk, vulnerability or exposure to the enterprise for inclusion in the IS annual audit plan. Risk Used to manage the project delivery and project benefit risk.

Risk avoidance

The process for systematically avoiding risk, constituting one approach to managing risk.

Risk management

The coordinated activities to direct and control an enterprise with regard to risk. In the International Standard, the term "control" is used as a synonym for "measure." (ISO/IEC Guide 73:2002) One of the governance objectives.

Risk mitigation

The management of risk through the use of countermeasures and controls.

Risk reduction

The implementation of controls or countermeasures to reduce the likelihood or impact of a risk to a level within the organization’s risk tolerance.

Risk tolerance

The acceptable level of variation that management is willing to allow for any particular risk as the enterprise pursues its objectives.

Risk transfer

The process of assigning risk to another enterprise, usually through the purchase of an insurance policy or by outsourcing the service.

Risk treatment

The process of selection and implementation of measures to modify risk (ISO/IEC Guide 73:2002).

Root cause analysis

A process of diagnosis to establish the origins of events, which can be used for learning from consequences, typically from errors and problems.

Rootkit

A software suite designed to aid an intruder in gaining unauthorized administrative access to a computer system.

Router

A networking device that can send (route) data packets from one local area network (LAN) or wide area network (WAN) to another, based on addressing at the network layer (Layer 3) in the open systems interconnection (OSI) model.

RSA

A public key cryptosystem developed by R. Rivest, A. Shamir and L. Adleman used for both encryption and digital signatures. Has two different keys, the public encryption key and the secret decryption key. The strength of this depends on the difficulty of the prime number factorization.

Safeguard

A practice, procedure or mechanism that reduces risk.

Secure Electronic Transaction (SET)

A standard that will ensure that credit card and associated payment order information travels safely and securely between the various involved parties on the Internet.

Secure Multipurpose Internet Mail Extensions (S/MIME)

Provides cryptographic security services for electronic messaging applications: authentication, message integrity and nonrepudiation of origin (using digital signatures) and privacy and data security (using encryption) to provide a consistent way to send and receive MIME data (RFC 2311).

Secure Socket Layer (SSL)

A protocol that is used to transmit private documents through the Internet. This protocol uses a private key to encrypt the data that are to be transferred through the SSL connection.

Secure Hypertext transfer protocol (S/HTTP)

An application layer protocol, S/HTTP transmits individual messages or pages securely between a web client and server by establishing an SSL-type connection.

Secure Shell (SSH)

Network protocol that uses cryptography to secure communication, remote command line login and remote command execution between two networked computers.

Security as a Service (SecaaS)

The next generation of managed security services dedicated to the delivery, over the Internet, of specialized information-security services.

Security metrics

A standard of measurement used in management of security-related activities.

Security perimeter

The boundary that defines the area of security concern and security policy coverage.

Segmentation

Network segmentation is the process of logically grouping network assets, resources, and applications together into compartmentalized areas that have no trust of each other.

Segregation/separation of duties (SoD)

A basic internal control that prevents or detects errors and irregularities by assigning to separate individuals the responsibility for initiating and recording transactions and for the custody of assets.

Sensitivity

A measure of the impact that improper disclosure of information may have on an enterprise.

Service delivery objective (SDO)

Directly related to the business needs, SDO is the level of services to be reached during the alternate process mode until the normal situation is restored.

Service level agreement (SLA)

An agreement, preferably documented, between a service provider and the customer(s)/user(s) that defines minimum performance targets for a service and how they will be measured.

Simple mail transfer protocol (SMTP)

The standard electronic mail (email) protocol on the Internet.

Single factor authentication (SFA)

Authentication process that requires only the user ID and password to grant access.

Smart card

A small electronic device that contains electronic memory, and possibly an embedded integrated circuit. These are used for a number of purposes including the storage of digital certificates or digital cash, or they can be used as a token to authenticate users.

Sniffing

The process by which data traversing a network are captured or monitored.

Social engineering

An attack based on deceiving users or administrators at the target site into revealing confidential or sensitive information.

Software as a Service (SaaS)

Offers the capability to use the provider’s applications running on cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email).

Source routing specification

A transmission technique where the sender of a packet can specify the route that packet should follow through the network.

Spam

Computer-generated messages sent as unsolicited advertising.

Spear phishing

An attack where social engineering techniques are used to masquerade as a trusted party to obtain important information such as passwords from the victim.

Spoofing

Faking the sending address of a transmission in order to gain illegal entry into a secure system.

Spyware

Software whose purpose is to monitor a computer user’s actions (e.g., web sites visited) and report these actions to a third party, without the informed consent of that machine’s owner or legitimate user. A particularly malicious form of spyware is software that monitors keystrokes to obtain passwords

SQL injection

Results from failure of the application to appropriately validate input. When specially crafted user-controlled input consisting of SQL syntax is used without proper validation as part of SQL queries, it is possible to glean information from the database in ways not envisaged during application design. (MITRE)

Stateful inspection

A firewall architecture that tracks each connection traversing all interfaces of the firewall and makes sure they are valid.

Statutory requirements

Laws created by government institutions.

Supervisory control and data acquisition (SCADA)

Systems used to control and monitor industrial and manufacturing processes, and utility facilities.

Switches

Typically associated as a data link layer device, switches enable local area network (LAN) segments to be created and interconnected, which has the added benefit of reducing collision domains in Ethernet-based networks.

Symmetric key encryption

System in which a different key (or set of keys) is used by each pair of trading partners to ensure that no one else can read their messages. The same key is used for encryption and decryption. See also Private Key Cryptosystem.

System development lifecycle (SDLC)

The phases deployed in the development or acquisition of a software system. An approach used to plan, design, develop, test and implement an application system or a major modification to an application system.

System hardening

A process to eliminate as many security risks as possible by removing all nonessential software programs, protocols, services and utilities from the system.

Tangible asset

Any assets that has physical form.

Target

Person or asset selected as the aim of an attack.

Telnet

Network protocol used to enable remote access to a server computer. Commands typed are run on the remote server.

Threat

Anything (e.g., object, substance, human) that is capable of acting against an asset in a manner that can result in harm. A potential cause of an unwanted incident (ISO/IEC 13335).

Threat agent

Methods and things used to exploit a vulnerability. Examples include determination, capability, motive and resources.

Threat analysis/assessment

An evaluation of the type, scope and nature of events or actions that can result in adverse consequences; identification of the threats that exist against enterprise assets. Usually defines the level of threat and the likelihood of it materializing.

Threat event

Any event during which a threat element/actor acts against an asset in a manner that has the potential to directly result in harm.

Threat vector

The path or route used by the adversary to gain access to the target.

Timelines

Chronological graphs where events related to an incident can be mapped to look for relationships in complex cases. Can provide simplified visualization for presentation to management and other nontechnical audiences.

Token

A device that is used to authenticate a user, typically in addition to a username and password. Usually a device the size of a credit card that displays a pseudo random number that changes every few minutes.

Topology

The physical layout of how computers are linked together. Examples of topology include ring, star and bus.

Total cost of ownership (TCO)

Includes the original cost of the computer plus the cost of: software, hardware and software upgrades, maintenance, technical support, training, and certain activities performed by users.

Transmission control protocol (TCP)

A connection-based Internet protocol that supports reliable data transfer connections. Packet data are verified using checksums and retransmitted if they are missing or corrupted. The application plays no part in validating the transfer.

Transmission control protocol/Internet protocol (TCP/IP)

Provides the basis for the Internet; a set of communication protocols that encompass media access, packet transport, session communication, file transfer, electronic mail (email), terminal emulation, remote file access and network management.

Transport Layer Security (TLS)

A protocol that provides communications privacy over the Internet. The protocol allows client-server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery. Composed of two layers: the TLS Record Protocol and the TLS Handshake Protocol.

Triple DES (3DES)

A block cipher created from the Data Encryption Standard (DES) cipher by using it three times.

Trojan horse

Purposefully hidden malicious or damaging code within an authorized computer program. Unlike viruses, they do not replicate themselves, but they can be just as destructive to a single computer.

Tunnel

The paths that the encapsulated packets follow in an Internet virtual private network (VPN).

Tunnel mode

Used to protect traffic between different networks when traffic must travel through intermediate or untrusted networks. Encapsulates the entire IP packet with and AH or ESP header and an additional IP header.

Two factor authentication

The use of two independent mechanisms for authentication, (e.g., requiring a smart card and a password) typically the combination of something you know, are or have.

Uncertainty

The difficulty of predicting an outcome due to limited knowledge of all components.

Uniform resource locator (URL)

The string of characters that form a web address.

User datagram protocol (UDP)

A connectionless Internet protocol that is designed for network efficiency and speed at the expense of reliability. A data request by the client is served by sending packets without testing to verify whether they actually arrive at the destination, not whether they were corrupted in transit.

User interface impersonation

Can be a pop-up ad that impersonates a system dialog, an ad that impersonates a system warning, or an ad that impersonates an application user interface in a mobile device.

User mode

Used for the execution of normal system activities.

User provisioning

A process to create, modify, disable and delete user accounts and their profiles across IT infrastructure and business applications.

Value

The relative worth or importance of an investment for an enterprise, as perceived by its key stakeholders, expressed as total life cycle benefits net of related costs, adjusted for risk and (in the case of financial value) the time value of money.

Vertical defense in depth

Controls are placed at different system layers – hardware, operating system, application, database or user levels.

Virtual local area network (VLAN)

Logical segmentation of a LAN into different broadcast domains. Set up by configuring ports on a switch, so devices attached to these ports may communicate as if they were attached to the same physical network segment, although the devices are located on different LAN segments.

Virtual private network (VPN)

A secure private network that uses the public telecommunications infrastructure to transmit data. In contrast to a much more expensive system of owned or leased lines that can only be used by one company, used by enterprises for both extranets and wide areas of intranets.

Virtual private network (VPN) concentrator

A system used to establish VPN tunnels and handle large numbers of simultaneous connections. This system provides authentication, authorization and accounting services.

Virtualization

The process of adding a "guest application" and data onto a "virtual server," recognizing that the guest application will ultimately part company from this physical server.

Virus

A program with the ability to reproduce by modifying other programs to include a copy of itself. May contain destructive code that can move into multiple programs, data files or devices on a system and spread through multiple systems in a network.

Virus signature file

The file of virus patterns that are compared with existing files to determine whether they are infected with a virus or worm.

Voice over Internet Protocol (VoIP)

Also called IP Telephony, Internet Telephony and Broadband Phone, a technology that makes it possible to have a voice conversation over the Internet or over any dedicated Internet Protocol (IP) network instead of over dedicated voice transmission lines.

Volatile data

Data that changes frequently and can be lost when the system’s power is shut down.

Vulnerability

A weakness in the design, implementation, operation or internal control of a process that could expose the system to adverse threats from threat events.

Vulnerability analysis/assessment

A process of identifying and classifying vulnerabilities.

Vulnerability scanning

An automated process to proactively identify security weaknesses in a network or individual system.

Warm site

Similar to a hot site but not fully equipped with all of the necessary hardware needed for recovery.

Web hosting

The business of providing the equipment and services required to host and maintain files for one or more web sites and provide fast Internet connections to those sites. Most hosting is "shared," which means that web sites of multiple companies are on the same server to share/reduce costs.

Web server

Using the client-server model and the World Wide Web’s HyperText Transfer Protocol (HTTP), Web Server is a software program that serves web pages to users.

Well known ports

0 through 1023: Controlled and assigned by the Internet Assigned Numbers Authority (IANA), and on most systems can be used only by system (or root) processes or by programs executed by privileged users.

Wide area network (WAN)

A computer network connecting different remote locations that may range from short distances, such as a floor or building, to extremely long transmissions that encompass a large region or several countries.

WiFi protected access (WPA)

created in response to several serious weaknesses that researchers found in the previous system, Wired Equivalent Privacy (WEP). Iimplements the majority of the IEEE 802.11i standard, and was intended as an intermediate measure to take the place of WEP while 802.11i was prepared.

WiFi protected access II (WPA2)

Wireless security protocol that supports 802.11i encryption standards to provide greater security. This protocol uses Advanced Encryption Standards (AES) and Temporal Key Integrity Protocol (TKIP) for stronger encryption.

Wired equivalent privacy (WEP)

was intended to provide comparable confidentiality to a traditional wired network (in particular, it does not protect users of the network from each other), hence the name. Several serious weaknesses were identified by cryptanalysts, and this was superseded by Wi-Fi Protected Access (WPA)

Wireless local area network (WLAN)

Two or more systems networked using a wireless distribution method.

Worm

A programmed network attack in which a self-replicating program does not attach itself to programs, but rather spreads independently of users’ action.

Write blocker

A devices that allows the acquisition of information on a drive without creating the possibility of accidentally damaging the drive.

Write protect

The use of hardware or software to prevent data to be overwritten or deleted.

Zero day exploit

A vulnerability that is exploited before the software creator/vendor is even aware of its existence. Appendices

Attenuation

Reduction of signal strength during transmission.