Information Security Definitions

This glossary explains the meaning of key words and phrases that information technology (IT) and business professionals use when discussing IT security and related software products. You can find additional definitions by visiting WhatIs.com or using the search box below.

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I
What is identity and access management? Guide to IAM

Identity and access management (IAM) is a framework of business processes, policies and technologies that facilitates the management of electronic or digital identities.
What is incident response? Plans, teams and tools

Incident response is an organized, strategic approach to detecting and managing cyber attacks in ways that minimize damage, recovery time and total costs.
J
juice jacking

Juice jacking is a security exploit in which an infected USB charging station is used to compromise devices that connect to it.
K
Kerberos

Kerberos is a protocol for authenticating service requests between trusted hosts across an untrusted network, such as the internet.
key fob

A key fob is a small, programmable device that provides access to a physical object.

keylogger (keystroke logger or system monitor)

A keylogger, sometimes called a keystroke logger or keyboard capture, is a type of surveillance technology used to monitor and record each keystroke on a specific computer.
knowledge-based authentication

Knowledge-based authentication (KBA) is an authentication method in which users are asked to answer at least one secret question.
L
LEAP (Lightweight Extensible Authentication Protocol)

LEAP (Lightweight Extensible Authentication Protocol) is a Cisco-proprietary version of EAP, the authentication protocol used in wireless networks and Point-to-Point connections. LEAP is designed to provide more secure authentication for 802.11 WLANs (wireless local area networks) that support 802.1X port access control.
logic bomb

A logic bomb is a string of malicious code that is inserted intentionally into a program to harm a network when certain conditions are met.
logon (or login)

In computing, a logon is a procedure that enables an entity to access a secure system such as an operating system, application, service, website or other resource.
Luhn algorithm (modulus 10)

The Luhn algorithm, also called modulus 10 or modulus 10 algorithm, is a simple mathematical formula used to validate a user's identification numbers.
M
macro virus

A macro virus is a computer virus written in the same macro language used to create software programs such as Microsoft Excel or Word.
mail bomb

A mail bomb is a form of a denial-of-service (DoS) attack designed to overwhelm an inbox or inhibit a server by sending a massive number of emails to a specific person or system.
malware

Malware, or malicious software, is any program or file that is intentionally harmful to a computer, network or server.
man in the browser (MitB)

Man in the browser (MitB) is a security attack where the perpetrator installs a Trojan horse on the victim's computer that is capable of modifying that user's web transactions.
mandatory access control (MAC)

Mandatory access control (MAC) is a security strategy that restricts the ability individual resource owners have to grant or deny access to resource objects in a file system.
MD5

The MD5 (message-digest algorithm) hashing algorithm is a one-way cryptographic function that accepts a message of any length as input and returns as output a fixed-length digest value to be used for authenticating the original message.
Melissa virus

Melissa was a type of email virus that initially become an issue in early 1999.
message authentication code (MAC)

A message authentication code (MAC) is a cryptographic checksum applied to a message in network communication to guarantee its integrity and authenticity.
messaging security

Messaging security is a subcategory of unified threat management, or UTM, focused on securing and protecting an organization's communication infrastructure.
metamorphic and polymorphic malware

Metamorphic and polymorphic malware are two types of malicious software (malware) that can change their code as they propagate through a system.
MICR (magnetic ink character recognition)

MICR (magnetic ink character recognition) is a technology invented in the 1950s that's used to verify the legitimacy or originality of checks and other paper documents.
micro VM (micro virtual machine)

A micro VM (micro virtual machine) is a virtual machine program that serves to isolate an untrusted computing operation from a computer's host operating system.
Microsoft Defender for Endpoint (formerly Windows Defender ATP)

Microsoft Defender for Endpoint -- formerly Microsoft Defender Advanced Threat Protection or Windows Defender ATP -- is an endpoint security platform designed to help enterprise-class organizations prevent, detect and respond to security threats.
Microsoft Schannel (Microsoft Secure Channel)

The Microsoft Secure Channel, or Schannel, is a security support package that facilitates the use of Secure Sockets Layer (SSL) and Transport Layer Security (TLS) encryption on Windows platforms.
Mitre ATT&CK framework

The Mitre ATT&CK (pronounced "miter attack") framework is a free, globally accessible framework that provides comprehensive and up-to-date cyber threat information to organizations looking to strengthen their cybersecurity strategies.
mobile authentication

Mobile authentication is the verification of a user's identity via a mobile device using one or more authentication methods for secure access.
multifactor authentication

Multifactor authentication (MFA) is an account login process that requires multiple methods of authentication from independent categories of credentials to verify a user's identity for a login or other transaction.
mutual authentication

Mutual authentication, also called two-way authentication, is a process or technology in which both entities in a communications link authenticate each other.
N
national identity card

A national identity card is a portable document, typically a plasticized card with digitally embedded information, that is used to verify aspects of a person's identity.
National Security Agency (NSA)

The National Security Agency (NSA) is a federal government intelligence agency that is part of the United States Department of Defense and is managed under the authority of the director of national intelligence (DNI).
network vulnerability scanning

Network vulnerability scanning is the process of inspecting and reporting potential vulnerabilities and security loopholes on a computer, network, web application or other device, including firewalls, switches, routers and wireless access points.
next-generation firewall (NGFW)

A next-generation firewall (NGFW) is part of the third generation of firewall technology that can be implemented in hardware or software.
NICE Framework (National Initiative for Cybersecurity Education Cybersecurity Workforce Framework)

The NICE Framework (National Initiative for Cybersecurity Education Cybersecurity Workforce Framework) is a reference resource that classifies the typical skill requirements and duties of cybersecurity workers.
Nimda

First appearing on September 18, 2001, Nimda is a computer virus that caused traffic slowdowns as it rippled across the internet.
NIST Cybersecurity Framework

The NIST Cybersecurity Framework (NIST CSF) is a policy framework surrounding IT infrastructure security.
nonrepudiation

Nonrepudiation ensures that no party can deny that it sent or received a message via encryption and/or digital signatures or approved some information.
North American Electric Reliability Corporation Critical Infrastructure Protection (NERC CIP)

The North American Electric Reliability Corporation Critical Infrastructure Protection (NERC CIP) plan is a set of standards aimed at regulating, enforcing, monitoring and managing the security of the Bulk Electric System (BES) in North America.
O
obfuscation

Obfuscation means to make something difficult to understand.
Occupational Safety and Health Administration (OSHA)

The Occupational Safety and Health Administration (OSHA) is responsible for protecting worker health and safety in the United States.
OCSP (Online Certificate Status Protocol)

OCSP (Online Certificate Status Protocol) is one of two common schemes used to maintain the security of a server and other network resources.
one-time pad

In cryptography, a one-time pad is a system in which a randomly generated private key is used only once to encrypt a message that is then decrypted by the receiver using a matching one-time pad and key.
one-time password (OTP)

A one-time password (OTP) is an automatically generated numeric or alphanumeric string of characters that authenticates the user for a single transaction or login session.
Open Source Hardening Project

The Open Source Hardening Project is an initiative of the United States Department of Homeland Security, created to improve the security of open source code. Because the infrastructure of the Internet, financial institutions and many other critcal systems in the U.S. run on open source software, the security of these applications is crucial... (Continued)
Open System Authentication (OSA)

Open System Authentication (OSA) is a process by which a computer could gain access to a wireless network that uses the Wired Equivalent Privacy (WEP) protocol.
operational risk

Operational risk is the risk of losses caused by flawed or failed processes, policies, systems or events that disrupt business operations.
OPSEC (operations security)

OPSEC (operations security) is a security and risk management process and strategy that classifies information, then determines what is required to protect sensitive information and prevent it from getting into the wrong hands.
orphan account

An orphan account, also referred to as an orphaned account, is a user account that can provide access to corporate systems, services and applications but does not have a valid owner.
out-of-band authentication

Out-of-band authentication is a type of two-factor authentication that requires a secondary verification method through a separate communication channel along with the typical ID and password. Out-of-band authentication is often used in financial institutions and other organizations with high security requirements.
P
PA-DSS (Payment Application Data Security Standard)

Payment Application Data Security Standard (PA-DSS) is a set of requirements intended to help software vendors develop secure payment applications for credit card transactions.
parameter tampering

Parameter tampering is a type of web-based cyber attack in which certain parameters in a URL are changed without a user's authorization.
pass the hash attack

A pass the hash attack is an exploit in which an attacker steals a hashed user credential and -- without cracking it -- reuses it to trick an authentication system into creating a new authenticated session on the same network.
passphrase

A passphrase is a sentencelike string of words used for authentication that is longer than a traditional password, easy to remember and difficult to crack.
password

A password is a string of characters used to verify the identity of a user during the authentication process.
password cracking

Password cracking is the process of using an application program to identify an unknown or forgotten password to a computer or network resource.
password manager

A password manager is a technology tool that helps internet users create, save, manage and use passwords across different online services.
password salting

Password salting is a technique to protect passwords stored in databases by adding a string of 32 or more characters and then hashing them.
passwordless authentication

Passwordless authentication is signing into a service without using a password.
Patch Tuesday

Patch Tuesday is the unofficial name of Microsoft's monthly scheduled release of security fixes for the Windows operating system (OS) and other Microsoft software.
payload (computing)

In computing, a payload is the carrying capacity of a packet or other transmission data unit.
PCI assessment

A PCI assessment is an audit of the 12 credit card transaction compliance requirements required by the Payment Card Industry Data Security Standard.
PCI compliance

PCI compliance is adherence to the set of policies and procedures developed to protect credit, debit and cash card transactions and prevent the misuse of cardholders' personal information.
PCI DSS (Payment Card Industry Data Security Standard)

The Payment Card Industry Data Security Standard (PCI DSS) is a widely accepted set of policies and procedures intended to optimize the security of credit, debit and cash card transactions and protect cardholders against misuse of their personal information.
PCI DSS 12 requirements

The PCI DSS 12 requirements are a set of security controls businesses must implement to protect credit card data and comply with the Payment Card Industry Data Security Standard (PCI DSS).
PCI DSS merchant levels

Payment Card Industry Data Security Standard (PCI DSS) merchant levels rank merchants based on their number of transactions per year to outline compliance verification requirements.
Pegasus malware

Pegasus malware is spyware that can hack any iOS or Android device and steal a variety of data from the infected device, including text messages, emails, key logs, audio and information from installed applications, such as Facebook or Instagram.
pen testing (penetration testing)

A penetration test, also called a pen test or ethical hacking, is a cybersecurity technique that organizations use to identify, test and highlight vulnerabilities in their security posture.
personally identifiable information (PII)

Personally identifiable information (PII) is any data that could potentially identify a specific individual.
pharming

Pharming is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting users to fraudulent websites without their knowledge or consent.
phishing

Phishing is a fraudulent practice in which an attacker masquerades as a reputable entity or person in an email or other form of communication.
physical security

Physical security is the protection of personnel, hardware, software, networks and data from physical actions and events that could cause serious loss or damage to an enterprise, agency or institution.
PKI (public key infrastructure)

PKI (public key infrastructure) is the underlying framework that enables entities -- users and servers -- to securely exchange information using digital certificates.
plaintext

In cryptography, plaintext is usually ordinary readable text before it is encrypted into ciphertext or after it is decrypted.
Plundervolt

Plundervolt is the name of an undervolting attack that targeted Intel central processing units (CPUs).
polymorphic virus

A polymorphic virus is a harmful, destructive or intrusive type of malware that can change or 'morph,' making it difficult to detect with antimalware programs.
possession factor

The possession factor, in a security context, is a category of user authentication credentials based on items that the user has with them, typically a hardware device such as a security token or a mobile phone used in conjunction with a software token.
post-quantum cryptography

Post-quantum cryptography, also known as quantum encryption, is the development of cryptographic systems for classical computers that can prevent attacks launched by quantum computers.
potentially unwanted program (PUP)

A potentially unwanted program (PUP) is a program that may be unwanted, despite the possibility that users consented to download it.
Pretty Good Privacy (PGP)

Pretty Good Privacy or PGP was a popular program used to encrypt and decrypt email over the internet, as well as authenticate messages with digital signatures and encrypted stored files.
principle of least privilege (POLP)

The principle of least privilege (POLP) is a concept in computer security that limits users' access rights to only what is strictly required to do their jobs.
privacy impact assessment (PIA)

A privacy impact assessment (PIA) is a method for identifying and assessing privacy risks throughout the development lifecycle of a program or system.
private CA (private PKI)

A private CA is an enterprise-specific certificate authority that functions like a publicly trusted CA.
private key

A private key, also known as a secret key, is a variable in cryptography that is used with an algorithm to encrypt and decrypt data.
privilege creep

Privilege creep is the gradual accumulation of access rights beyond what individuals need to do their job.
privileged access management (PAM)

Privileged access management (PAM) is the combination of tools and technology used to secure, control and monitor access to an organization's critical information and resources.
privileged identity management (PIM)

Privileged identity management (PIM) is the monitoring and protection of superuser accounts that hold expanded access to an organization's IT environments.
promiscuous mode

In computer networking, promiscuous mode is a mode of operation, as well as a security, monitoring and administration technique.
proof of concept (PoC) exploit

A proof of concept (PoC) exploit is a non-harmful attack against a computer or network. PoC exploits are not meant to cause harm, but to show security weaknesses within software.
Protected Extensible Authentication Protocol (PEAP)

Protected Extensible Authentication Protocol (PEAP) is a security protocol commonly used to protect wireless networks.
proxy firewall

A proxy firewall is a network security system that protects network resources by filtering messages at the application layer.
public key

In cryptography, a public key is a large numerical value that is used to encrypt data.
public key certificate

A public key certificate is a digitally signed document that serves to validate the sender's authorization and name.
Public-Key Cryptography Standards (PKCS)

Public-Key Cryptography Standards (PKCS) are a set of standard protocols, numbered from 1 to 15.
pure risk

Pure risk refers to risks that are beyond human control and result in a loss or no loss with no possibility of financial gain.
Q
quantum cryptography

Quantum cryptography is a method of encryption that uses the naturally occurring properties of quantum mechanics to secure and transmit data.
quantum key distribution (QKD)

Quantum key distribution (QKD) is a secure communication method for exchanging encryption keys only known between shared parties.
quantum supremacy

Quantum supremacy is the experimental demonstration of a quantum computer's dominance and advantage over classical computers by performing calculations previously impossible at unmatched speeds.
R
RADIUS (Remote Authentication Dial-In User Service)

RADIUS (Remote Authentication Dial-In User Service) is a client-server protocol and software that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service.
RAT (remote access Trojan)

A RAT (remote access Trojan) is malware an attacker uses to gain full administrative privileges and remote control of a target computer.
registration authority (RA)

A registration authority (RA) is an authority in a network that verifies user requests for a digital certificate and tells the certificate authority (CA) to issue it.