Cybersecurity Glossary


Just a note on the Cybersecurity Glossary

Cybersecurity Glossary – An alphabetical listing of cybersecurity terms with definitions to help standardize some of the vocabulary out there and keep everyone on the same page. This is a dynamic glossary and I will modify it as new information and omissions are found.

Updated: 21 October 2023


Absolute file path: The full file path, which starts from the root

Access controls: Security controls that manage access, authorization, and accountability of information

Active packet sniffing: A type of attack where data packets are manipulated in transit

Address Resolution Protocol (ARP): A network protocol used to determine the MAC address of the next router or device on the path

Advanced persistent threat (APT): An instance when a threat actor maintains unauthorized access to a system for an extended period of time

Adversarial artificial intelligence (AI): A technique that manipulates artificial intelligence (AI) and machine learning (ML) technology to conduct attacks more efficiently

Adware: A type of legitimate software that is sometimes used to display digital advertisements in applications

Algorithm: A set of rules used to solve a problem

Analysis: The investigation and validation of alerts

Angler phishing: A technique where attackers impersonate customer service representatives on social media

Anomaly-based analysis: A detection method that identifies abnormal behavior

Antivirus software: A software program used to prevent, detect, and eliminate malware and viruses

Application: A program that performs a specific task

Application programming interface (API) token: A small block of encrypted code that contains information about a user

Argument (Linux): Specific information needed by a command

Argument (Python): The data brought into a function when it is called

Array: A data type that stores data in a comma-separated ordered list

Assess: The fifth step of the NIST RMF that means to determine if established controls are implemented correctly

Access control — The means and mechanisms of managing access to and use of resources by users. There are three primary forms of access control: DAC, MAC, and RBAC. DAC (Discretionary Access Control) manages access through the use of on-object ACLs (Access Control Lists), which indicate which users have been granted (or denied) specific privileges or permissions on that object. MAC (Mandatory Access Control) restricts access by assigning each subject and object a classification or clearance level label; resource use is then controlled by limiting access to those subjects with equal or superior labels to that of the object. RBAC (Role Base Access Control) controls access through the use of job labels, which have been assigned the permissions and privilege needed to accomplish the related job tasks.

Anti-virus (anti-malware) — A security program designed to monitor a system for malicious software. Once malware is detected, the AV program will attempt to remove the offending item from the system or may simply quarantine the file for further analysis by an administrator. It is important to keep AV software detection databases current in order to have the best chance of detecting known forms of malware.

Antivirus software — A software program that monitors a computer system or network communications for known examples of malicious code and then attempts to remove or quarantine the offending items. (Also known as Malware Scanner.) Most anti-virus (AV) products use a pattern recognition or signature matching system to detect the presence of known malicious code. Some AV products have adopted technologies to potentially detect new and unknown malware. These technologies include anomaly detection (i.e. watch for programs which violate specific rules), behavioral detection (i.e. watch for programs that have behaviors that are different from the normal baseline of behavior of the system), and heuristic detection (i.e. watch for programs that exhibit actions which are known to be those of confirmed malware; it is a type of technological profiling).

APT (Advanced Persistent Threat) — A security breach that enables an attacker to gain access or control over a system for an extended period of time usually without the owner of the system being aware of the violation. Often an APT takes advantage of numerous unknown vulnerabilities or zero day attacks, which allow the attacker to maintain access to the target even as some attack vectors are blocked.

Asset: An item perceived as having value to an organization

Asset classification: The practice of labeling assets based on sensitivity and importance to an organization

Asset inventory: A catalog of assets that need to be protected

Asset management: The process of tracking assets and the risks that affect them

Asymmetric encryption: The use of a public and private key pair for encryption and decryption of data

Attack surface: All the potential vulnerabilities that a threat actor could exploit

Attack tree: A diagram that maps threats to assets

Attack vectors: The pathways attackers use to penetrate security defenses

Authentication: The process of verifying who someone is

Authorization: The concept of granting access to specific resources in a system

Authorize: The sixth step of the NIST RMF that refers to being accountable for the security and privacy risks that might exist in an organization

Automation: The use of technology to reduce human and manual effort to perform common and repetitive tasks

Availability: The idea that data is accessible to those who are authorized to access it


backing up : Creating a duplicate copy of data onto a separate physical storage device or online/cloud storage solution. A backup is the only insurance against data loss. With a backup, damaged or lost data files can be restored. Backups should be created on a regular, periodic basis such as daily. A common strategy is based on the 3-2-1 rule: you should have three copies of your data – the original and 2 backups; you should use 2 different types of media (such as a physical media (such as a hard drive or tape) and a cloud storage solution); and do not store the three copies of data in 1 plane (i.e. backups should be stored offsite). It is important to store backups for disaster recovery at an offsite location in order to insure they are not damaged by the same event that would damage the primary production location. However, additional onsite backups can be retained for resolving minor issues such as accidental file deletion or hard drive failure.

Baiting: A social engineering tactic that tempts people into compromising their security

Bandwidth: The maximum data transmission capacity over a network, measured by bits per second

Baseline configuration (baseline image): A documented set of specifications within a system that is used as a basis for future builds, releases, and updates

Bash: The default shell in most Linux distributions

Basic auth: The technology used to establish a user’s request to access a server

Basic Input/Output System (BIOS): A microchip that contains loading instructions for the computer and is prevalent in older systems

BCP (Business Continuity Planning) :  A business management plan used to resolve issues that threaten core business tasks. (Also known as Business Continuity Management.) The goal of BCP is to prevent the failure of mission critical processes when they have be harmed by a breach or accident. Once core business tasks have been stabilized, BCP dictates the procedure to return the environment back to normal conditions. BCP is used when the normal security policy has failed to prevent harm from occurring, but before the harm has reached the level of fully interrupting mission critical processes, which would trigger the Disaster Recovery Process (DRP).

Biometrics: The unique physical characteristics that can be used to verify a person’s identity

Bit: The smallest unit of data measurement on a computer

Behavior monitoring: Recording the events and activities of a system and its users. The recorded events are compared against security policy and behavioral baselines to evaluate compliance and/or discover violations. Behavioral monitoring can include the tracking of trends, setting of thresholds and defining responses. Trend tracking can reveal when errors are increasing requiring technical support services, when abnormal load levels occur indicating the presence of malicious code, or when production work levels increase indicating a need to expand capacity. Thresholds are used to define the levels of activity or events above which are of concern and require a response. The levels below the threshold are recorded but do not trigger a response. Responses can be to resolve conflicts, handle violations, prevent downtime or improve capabilities.

Blacklist : A security mechanism prohibiting the execution of those programs on a known malicious or undesired list of software. The blacklist is a list of specific files known to be malicious or otherwise are unwanted. Any program on the list is prohibited from executing while any other program, whether benign or malicious, is allowed to execute by default. (See whitelist.)

Block cipher: A type of symmetric encryption algorithm that divides data into fixed length sections and then performs the encryption or decryption operation on each block. The action of dividing a data set into blocks enables the algorithm to encrypt data of any size.

Boolean data: Data that can only be one of two values: either True or False

Bootloader: A software program that boots the operating system

Botnet: A collection of computers infected by malware that are under the control of a single threat actor, known as the “bot-herder”

Bracket notation: The indices placed in square brackets

Broken chain of custody: Inconsistencies in the collection and logging of evidence in the chain of custody

Brute force attack: The trial and error process of discovering private information

Botnet:  A collection of innocent computers which have been compromised by malicious code in order to run a remote control agent granting an attacker the ability to remotely take advantage of the system’s resources in order to perform illicit or criminal actions. These actions include DoS flooding attacks, hosting false Web services, spoofing DNS, transmitting SPAM, eavesdropping on network communications, recording VOIP communications and attempting to crack encryption or password hashes. Botnets can be comprised of dozens to over a million individual computers. The term botnet is a shortened form of robotic network.

Bug:  An error or mistake in software coding or hardware design or construction. A bug represents a flaw or vulnerability in a system discoverable by attackers and used as point of compromise. Attacks often use fuzzing technique (i.e. randomize testing tools) to locate previously unknown bugs in order to craft new exploits.

Bug bounty: Programs that encourage freelance hackers to find and report vulnerabilities

Built-in function: A function that exists within Python and can be called directly

Business continuity: An organization’s ability to maintain their everyday productivity by establishing risk disaster recovery plans

Business continuity plan (BCP): A document that outlines the procedures to sustain business operations during and after a significant disruption

Business Email Compromise (BEC): A type of phishing attack where a threat actor impersonates a known source to obtain financial advantage

BYOD (Bring Your Own Device) — A company’s security policy dictating whether or not workers can bring in their own devices into the work environment, whether or not such devices can be connected to the company network and to what extent that connection allows interaction with company resources. A BYOD policy can range from complete prohibition of personal devices being brought into the facility to allowing any device to be connected to the company network with full access to all company resources. Generally, a BYOD policy puts reasonable security limitations on which devices can be used on company property and severely limits access to sensitive company network resources. BYOD should address concerns such as data ownership, asset tracking, geo location, patching and upgrades, security applications (such as malware scanners, firewalls and IDS), storage segmentation, appropriate vs inappropriate applications, on-boarding, off-boarding, repair/replacement due to damage, legal concerns, internal investigations and law enforcement investigations and forensics.


Categorize: The second step of the NIST RMF that is used to develop risk management processes and tasks

CentOS: An open-source distribution that is closely related to Red Hat. Note: CentOS is at end of life and is not being developed.

Central Processing Unit (CPU): A computer’s main processor, which is used to perform general computing tasks on a computer

Chain of custody: The process of documenting evidence possession and control during an incident lifecycle

Chronicle: A cloud-native tool designed to retain, analyze, and search data

Cipher: An algorithm that encrypts information

ciphertext: The unintelligible and seeming random form of data that is produced by the cryptographic function of encryption. Ciphertext is produced by a symmetric algorithm when a data set is transformed by the encryption process using a selected key. Ciphertext can converted back into its original form (i.e. plain text) by performing the decryption process using the same symmetric encryption algorithm and the key used during the encryption process.

Clickjacking:  A malicious technique by which a victim is tricked into clicking on a URL, button or other screen object other than that intended by or perceived by the user. Clickjacking can be performed in many ways; one of which is to load a web page transparently behind another visible page in such a way that the obvious links and objects to click are facades, so clicking on an obvious link actually causes the hidden page’s link to be selected.

CND (Computer Network Defense) : The establishment of a security perimeter and of internal security requirements with the goal of defending a network against cyberattacks, intrusions and other violations. A CND is defined by a security policy and can be stress tested using vulnerability assessment and penetration testing measures.

Cloud-based firewalls: Software firewalls that are hosted by the cloud service provider

Cloud computing: The practice of using remote servers, applications, and network services that are hosted on the internet instead of on local physical devices

Cloud network: A collection of servers or computers that stores resources and data in remote data centers that can be accessed via the internet

Cloud security: The process of ensuring that assets stored in the cloud are properly configured and access to those assets is limited to authorized users

Command: An instruction telling the computer to do something

Command and control (C2): The techniques used by malicious actors to maintain communications with compromised systems

Command-line interface (CLI): A text-based user interface that uses commands to interact with the computer

Comment: A note programmers make about the intention behind their code

Common Event Format (CEF): A log format that uses key-value pairs to structure data and identify fields and their corresponding values

Common Vulnerabilities and Exposures (CVE®) list: An openly accessible dictionary of known vulnerabilities and exposures

Common Vulnerability Scoring System (CVSS): A measurement system that scores the severity of a vulnerability

Compliance: The process of adhering to internal standards and external regulations

Computer security incident response teams (CSIRT): A specialized group of security professionals that are trained in incident management and response

Computer virus: Malicious code written to interfere with computer operations and cause damage to data and software

Conditional statement: A statement that evaluates code to determine if it meets a specified set of conditions

Confidentiality: The idea that only authorized users can access specific assets or data

Confidential data: Data that often has limits on the number of people who have access to it

Confidentiality, integrity, availability (CIA) triad: A model that helps inform how organizations consider risk when setting up systems and security policies

Configuration file: A file used to configure the settings of an application

Containment: The act of limiting and preventing additional damage caused by an incident

Controlled zone: A subnet that protects the internal network from the uncontrolled zone

Cross-site scripting (XSS): An injection attack that inserts code into a vulnerable website or web application

Cracker:  The proper term to refer to an unauthorized attacker of computers, networks and technology instead of the misused term “hacker.” However, this term is not as widely used in the media; thus, the term hacker has become more prominent in-spite of the terms misuse. (See hacker.)

Critical infrastructure:  The physical or virtual systems and assets that are vital to an organization or country. If these systems are compromised, the result would be catastrophic. If an organization’s mission critical processes are interrupted, this could result in the organization ceasing to exist. If a country’s critical infrastructure is destroyed, it will have severe negative impact on national security, economic stability, citizen safety and health, transportation and communications.

Crowdsourcing: The practice of gathering information using public input and collaboration

Cryptographic attack: An attack that affects secure forms of communication between a sender and intended recipient

Cryptographic key: A mechanism that decrypts ciphertext

Cryptography: The process of transforming information into a form that unintended reader can’t understand

Cryptojacking: A form of malware that installs software to illegally mine cryptocurrencies

CVE Numbering Authority (CNA): An organization that volunteers to analyze and distribute information on eligible CVEs

Cyberespionage:  The unethical act of violating the privacy and security of an organization in order to leak data or disclose internal/private/confidential information. Cyberespionage can be performed by individuals, organization or governments for the direct purpose of causing harm to the violated entity to benefit individuals, organizations or governments.

Cybersecurity: The practice of ensuring confidentiality, integrity, and availability of information by protecting networks, devices, people, and data from unauthorized access or criminal exploitation

Cyber teams:  Groups of professional or amateur penetration testing specialists who are tasked with evaluating and potentially improving the security stance of an organization. Common cyber teams include the red, blue and purple/white teams. A red team is often used as part of a multi-team penetration test (i.e. security evaluation), which is responsible for attacking the target which is being defended by the blue team. A purple team or white team is either used as a reference between the attack/red and defense/blue teams; or this team can be used as an interpreter of the results and activities of the red and blue teams in order to maximize their effectiveness in the final results.


Data: Information that is translated, processed, or stored by a computer

Data at rest: Data not currently being accessed

Database: An organized collection of information or data

Data breach: The occurrence of disclosure of confidential information, access to confidential information, destruction of data assets or abusive use of a private IT environment. Generally, a data breach results in internal data being made accessible to external entities without authorization.

Data controller: A person that determines the procedure and purpose for processing data

Data custodian: Anyone or anything that’s responsible for the safe handling, transport, and storage of information

Data exfiltration: Unauthorized transmission of data from a system

Data integrity: A security benefit that verifies data is unmodified and therefore original, complete and intact. Integrity is verified through the use of cryptographic hashing. A hashing algorithm generates a fixed length output known as a hash value, fingerprint or MAC (Message Authenticating Code), which is derived from the input data but which does not contain the input data. This makes hashing a one-way operation. A hash is calculated before an event, and another hash is calculated after the event (an event can be a time frame of storage (i.e. data-at-rest) or an occurrence of transmission (i.e. data-in-transit); the two hashes are then compared using an XOR Boolean operation. If the two hashes exactly match (i.e. the XOR result is zero), then the data has retained its integrity. However, if the two hashes do not match exactly (i.e. the XOR result is a non-zero value), then something about the data changed during the event.

Data in transit: Data traveling from one point to another

Data in use: Data being accessed by one or more users

Data owner: The person who decides who can access, edit, use, or destroy their information

Data mining: The activity of analyzing and/or searching through data in order to find items of relevance, significance or value. The results of data mining are known as meta-data. Data mining can be a discovery of individual important data items, a summary or overview of numerous data items or a consolidation or clarification of a collection of data items.

Data packet: A basic unit of information that travels from one device to another within a network

Data point: A specific piece of information

Data processor: A person that is responsible for processing data on behalf of the data controller

Data protection officer (DPO): An individual that is responsible for monitoring the compliance of an organization’s data protection procedures

Data theft: The act of intentionally stealing data. Data theft can occur via data loss (physical theft) or data leakage (logical theft) event. Data loss occurs when a storage device is lost or stolen. Data leakage occurs when copies of data is possessed by unauthorized entities.

Data type: A category for a particular type of data item

Date and time data: Data representing a date and/or time

Debugger: A software tool that helps to locate the source of an error and assess its causes

Debugging: The practice of identifying and fixing errors in code

Defense in depth: A layered approach to vulnerability management that reduces risk

Denial of service (DoS) attack: An attack that targets a network or server and floods it with network traffic

Detect: A NIST core function related to identifying potential security incidents and improving monitoring capabilities to increase the speed and efficiency of detections

Detection: The prompt discovery of security events

Dictionary data: Data that consists of one or more key-value pairs

Digital certificate: A file that verifies the identity of a public key holder

Digital forensics: The practice of collecting and analyzing data to determine what has happened after an attack

Directory: A file that organizes where other files are stored

Disaster recovery plan: A plan that allows an organization’s security team to outline the steps needed to minimize the impact of a security incident

Distributed denial of service (DDoS) attack: A type of denial or service attack that uses multiple devices or servers located in different locations to flood the target network with unwanted traffic

Distributions: The different versions of Linux

DMZ (Demilitarized Zone): A segment or subnet of a private network where resources are hosted and accessed by the general public from the Internet. The DMZ is isolated from the private network using a firewall and is protected from obvious abuses and attacks from the Internet using a firewall. A DMZ can be deployed in two main configurations. One method is the screened subnet configuration, which has the structure of I-F-DMZ-F-LAN (i.e. internet, then firewall, then the DMZ, then another firewall, then the private LAN). A second method is the multi-homed firewall configuration, which has the structure of a single firewall with three interfaces, one connecting to the Internet, a second to the DMZ, and a third to the private LAN.

Documentation: Any form of recorded content that is used for a specific purpose

DOM-based XSS attack: An instance when malicious script exists in the webpage a browser loads

Domain Name System (DNS): A networking protocol that translates internet domain names into IP addresses

Drive-by download:  A type of web-based attack that automatically occurs based on the simple act of visiting a malicious or compromised/poisoned Web site. A drive-by download is accomplished by taking advantage of the default nature of a Web browser to execute mobile code, most often JavaScript, with little to no security restrictions. A drive-by download can install tracking tools, remote access backdoors, botnet agents, keystroke loggers or other forms of malicious utilities. In most cases, the occurrence of the infection based on the drive-by download is unnoticed by the user/victim.

Dropper: A program or a file used to install a rootkit on a target computer


Eavesdropping:  The act of listening in on a transaction, communication, data transfer or conversation. Eavesdropping can be used to refer to both data packet capture on a network link (also known as sniffing or packet capture) and to audio recording using a microphone (or listening with ears).

Encode: The act which transforms plaintext or cleartext (i.e. the original form of normal standard data) into ciphertext (i.e. the unintelligible and seeming random form of data that is produced by the cryptographic function of encryption). Ciphertext is produced by a symmetric encryption algorithm when a data set is transformed by the encryption process using a selected key (i.e. to encrypt or encode). Ciphertext can converted back into its original form (i.e. plaintext) by performing the decryption process using the same symmetric encryption algorithm and the same key used during the encryption process (i.e. decrypt or decode).

Encryption key: The secret number value used by a symmetric encryption algorithm to control the encryption and decryption process. A key is a number defined by its length in binary digits. Generally, the longer the key length, the more security (i.e. defense against confidentiality breaches) it provides. The length of the key also determines the key space, which is the range of values between the binary digits being all zeros and all ones from which the key can be selected.

Encapsulation: A process performed by a VPN service that protects your data by wrapping sensitive data in other data packets

Encryption: The process of converting data from a readable format to an encoded format

Endpoint: Any device connected on a network

Endpoint detection and response (EDR): An application that monitors an endpoint for malicious activity

Eradication: The complete removal of the incident elements from all affected systems

Escalation policy: A set of actions that outline who should be notified when an incident alert occurs and how that incident should be handled

Event: An observable occurrence on a network, system, or device

Exception: An error that involves code that cannot be executed even though it is syntactically correct

Exclusive operator: An operator that does not include the value of comparison

Exploit: A way of taking advantage of a vulnerability

Exposure: A mistake that can be exploited by a threat

External threat: Anything outside the organization that has the potential to harm organizational assets


False negative: A state where the presence of a threat is not detected

False positive: An alert that incorrectly detects the presence of a threat

Fileless malware: Malware that does not need to be installed by the user because it uses legitimate programs that are already installed to infect a computer

File path: The location of a file or directory

Filesystem Hierarchy Standard (FHS): The component of the Linux OS that organizes data

Filtering: Selecting data that match a certain condition

Final report: Documentation that provides a comprehensive review of an incident

Firewall: A network security device that monitors traffic to or from a network

Float data: Data consisting of a number with a decimal point

Foreign key: A column in a table that is a primary key in another table

Forward proxy server: A server that regulates and restricts a person’s access to the internet

Function: A section of code that can be reused in a program


Global variable: A variable that is available through the entire program

Graphical user interface (GUI): A user interface that uses icons on the screen to manage different tasks on the computer


Hacker: Any person or group who uses computers to gain unauthorized access to data

Hacktivist: A person who uses hacking to achieve a political goal

Hard drive: A hardware component used for long-term memory

Hardware: The physical components of a computer

Hash collision: An instance when different inputs produce the same hash value

Hash function: An algorithm that produces a code that can’t be decrypted

Hash table: A data structure that’s used to store and reference hash values

Health Insurance Portability and Accountability Act (HIPAA): A U.S. federal law established to protect patients’ health information

Honeypot: A system or resource created as a decoy vulnerable to attacks with the purpose of attracting potential intruders

Host-based intrusion detection system (HIDS): An application that monitors the activity of the host on which it’s installed

Hub: A network device that broadcasts information to every device on the network

Hypertext Transfer Protocol (HTTP): An application layer protocol that provides a method of communication between clients and website servers

Hypertext Transfer Protocol Secure (HTTPS): A network protocol that provides a secure method of communication between clients and website servers


Identify: A NIST core function related to management of cybersecurity risk and its effect on an organization’s people and assets

Identity and access management (IAM): A collection of processes and technologies that helps organizations manage digital identities in their environment

IDS (Intrusion Detection System): A security tool that attempts to detect the presence of intruders or the occurrence of security violations in order to notify administrators, enable more detailed or focused logging or even trigger a response such as disconnecting a session or blocking an IP address. An IDS is considered a more passive security tool as it detects compromises after they are already occurring rather than preventing them from becoming successful.

IEEE 802.11 (Wi-Fi): A set of standards that define communication for wireless LANs

Immutable: An object that cannot be changed after it is created and assigned a value

Implement: The fourth step of the NIST RMF that means to implement security and privacy plans for an organization

Improper usage: An incident type that occurs when an employee of an organization violates the organization’s acceptable use policies

Incident: An occurrence that actually or imminently jeopardizes, without lawful authority, the confidentiality, integrity, or availability of information or an information system; or constitutes a violation or imminent threat of violation of law, security policies, security procedures, or acceptable use policies

Incident escalation: The process of identifying a potential security incident, triaging it, and handing it off to a more experienced team member

Incident handler’s journal: A form of documentation used in incident response

Incident response: An organization’s quick attempt to identify an attack, contain the damage, and correct the effects of a security breach

Incident response plan: A document that outlines the procedures to take in each step of incident response

Inclusive operator: An operator that includes the value of comparison

Indentation: Space added at the beginning of a line of code

Index: A number assigned to every element in a sequence that indicates its position

Indicators of attack (IoA): The series of observed events that indicate a real-time incident

Indicators of compromise (IoC): Observable evidence that suggests signs of a potential security incident

Information privacy: The protection of unauthorized access and distribution of data

Information security (InfoSec): The practice of keeping data in all states away from unauthorized users

Injection attack: Malicious code inserted into a vulnerable application

Input validation: Programming that validates inputs from users and other programs

Integer data: Data consisting of a number that does not include a decimal point

Integrated development environment (IDE): A software application for writing code that provides editing assistance and error correction tools

Integrity: The idea that the data is correct, authentic, and reliable

Internal hardware: The components required to run the computer

Internal threat: A current or former employee, external vendor, or trusted partner who poses a security risk

Internet Control Message Protocol (ICMP): An internet protocol used by devices to tell each other about data transmission errors across the network

Internet Control Message Protocol flood (ICMP flood): A type of DoS attack performed by an attacker repeatedly sending ICMP request packets to a network server

Internet Protocol (IP): A set of standards used for routing and addressing data packets as they travel between devices on a network

Internet Protocol (IP) address: A unique string of characters that identifies the location of a device on the internet

Interpreter: A computer program that translates Python code into runnable instructions line by line

Intrusion prevention system (IPS): An application that monitors system activity for intrusive activity and takes action to stop the activity

IP spoofing: A network attack performed when an attacker changes the source IP of a data packet to impersonate an authorized system and gain access to a network

Iterative statement: Code that repeatedly executes a set of instructions


JBOH (JavaScript-Binding-Over-HTTP): A form of Android-focused mobile device attack that enables an attacker to be able to initiate the execution of arbitrary code on a compromised device. A JBOH attack often takes place or is facilitated through compromised or malicious apps.


KALI  LINUX : An open-source distribution of Linux that is widely used in the security industry

Kernel: The component of the Linux OS that manages processes and memory

Keylogger:  Any means by which the keystrokes of a victim are recorded as they are typed into the physical keyboard. A keylogger can be a software solution or a hardware device used to capture anything that a user might type in including passwords, answers to secret questions or details and information form e-mails, chats and documents.

Key-value pair: A set of data that represents two linked items:  A key and its corresponding value


Legacy operating system: An operating system that is outdated but still being used

Lessons learned meeting: A meeting that includes all involved parties after a major incident

Library: A collection of modules that provide code users can access in their programs

Link jacking:  A potentially unethical practice of redirecting a link to a middle-man or aggregator site or location rather than the original site the link seemed to indicate it was directed towards. For example, a news aggregation service may publish links that seem as if they point to the original source of their posted articles, but when a user discovers those links via search or through social networks, the links redirect back to the aggregation site and not the original source of the article.

Linux: An open-source operating system

List concatenation: The concept of combining two lists into one by placing the elements of the second list directly after the elements of the first list

List data: Data structure that consists of a collection of data in sequential form

Loader: Malicious code that launches after a user initiates a dropper program

Local Area Network (LAN): A network that spans small areas like an office building, a school, or a home

Local variable: A variable assigned within a function

Log: A record of events that occur within an organization’s systems

Log analysis: The process of examining logs to identify events of interest

Logging: The recording of events occurring on computer systems and networks

Logic error: An error that results when the logic used in code produces unintended results

Log management: The process of collecting, storing, analyzing, and disposing of log data

Loop condition: The part of a loop that determines when the loop terminates

Loop variable: A variable that is used to control the iterations of a loop


Malware: Software designed to harm devices or networks

Malware infection: An incident type that occurs when malicious software designed to disrupt a system infiltrates an organization’s computers or network

Media Access Control (MAC) address: A unique alphanumeric identifier that is assigned to each physical device on a network

Method: A function that belongs to a specific data type

Metrics: Key technical attributes such as response time, availability, and failure rate, which are used to assess the performance of a software application

MITRE: A collection of non-profit research and development centers

Modem: A device that connects your router to the internet and brings internet access to the LAN

Module: A Python file that contains additional functions, variables, classes, and any kind of runnable code

Monitor: The seventh step of the NIST RMF that means be aware of how systems are operating

Multi-factor authentication (MFA): A security measure that requires a user to verify their identity in two or more ways to access a system or network


nano: A command-line file editor that is available by default in many Linux distributions

National Institute of Standards and Technology (NIST) Cybersecurity Framework (CSF): A voluntary framework that consists of standards, guidelines, and best practices to manage cybersecurity risk

National Institute of Standards and Technology (NIST) Incident Response Lifecycle: A framework for incident response consisting of four phases: Preparation; Detection and Analysis; Containment, Eradication and Recovery, and Post-incident activity

National Institute of Standards and Technology (NIST) Special Publication (S.P.) 800-53: A unified framework for protecting the security of information systems within the U.S. federal government

Network: A group of connected devices

Network-based intrusion detection system (NIDS): An application that collects and monitors network traffic and network data

Network data: The data that’s transmitted between devices on a network

Network Interface Card (NIC): Hardware that connects computers to a network

Network log analysis: The process of examining network logs to identify events of interest

Network protocol analyzer (packet sniffer): A tool designed to capture and analyze data traffic within a network

Network protocols: A set of rules used by two or more devices on a network to describe the order of delivery and the structure of data

Network security: The practice of keeping an organization’s network infrastructure secure from unauthorized access

Network segmentation: A security technique that divides the network into segments

Network traffic: The amount of data that moves across a network

Non-repudiation: The concept that the authenticity of information can’t be denied

Notebook: An online interface for writing, storing, and running code

Numeric data: Data consisting of numbers


OAuth: An open-standard authorization protocol that shares designated access between applications

Object: A data type that stores data in a comma-separated list of key-value pairs

On-path attack: An attack where a malicious actor places themselves in the middle of an authorized connection and intercepts or alters the data in transit

Open-source intelligence (OSINT): The collection and analysis of information from publicly available sources to generate usable intelligence

Open systems interconnection (OSI) model: A standardized concept that describes the seven layers computers use to communicate and send data over the network

Open Web Application Security Project (OWASP): A non-profit organization focused on improving software security

Operating system (OS): The interface between computer hardware and the user

Operator: A symbol or keyword that represents an operation

Options: Input that modifies the behavior of a command

Order of volatility: A sequence outlining the order of data that must be preserved from first to last

OWASP (Open Web Application Security Project): An Internet community focused on understanding web technologies and exploitations. Their goal is to help anyone with a website improve the security of their site through defensive programming, design and configuration. Their approach includes understanding attacks in order to know how to defend against them. OWASP offers numerous tools and utilities related to website vulnerability evaluation and discovery as well as a significant amount of training and reference material related to all things web security.

OWASP Top 10: A globally recognized standard awareness document that lists the top 10 most critical security risks to web applications


Package: A piece of software that can be combined with other packages to form an application

Package manager: A tool that helps users install, manage, and remove packages or applications

Packet capture (P-cap): A file containing data packets intercepted from an interface or network

Packet sniffing: The practice of capturing and inspecting data packets across a network

Parameter (Python): An object that is included in a function definition for use in that function

Parrot: An open-source distribution that is commonly used for security

Parsing: The process of converting data into a more readable format

Passive packet sniffing: A type of attack where a malicious actor connects to a network hub and looks at all traffic on the network

Password attack: An attempt to access password secured devices, systems, networks, or data

Patch update: A software and operating system update that addresses security vulnerabilities within a program or product

Payment Card Industry Data Security Standards (PCI DSS): Any cardholder data that an organization accepts, transmits, or stores

Payment card skimmers: A malicious device used to read the contents of an ATM, debit or credit card when inserted into a POS (Point of Sale) payment system. A skimmer may be an internal component or an external addition. An attacker will attempt to use whatever means to imbed their skimmer into a payment system that will have the highest likelihood of not being detected and thus gather the most amount of financial information from victims.

Penetration test (pen test): A simulated attack that helps identify vulnerabilities in systems, networks, websites, applications, and processes

PEP 8 style guide: A resource that provides stylistic guidelines for programmers working in Python

Peripheral devices: Hardware components that are attached and controlled by the computer system

Permissions: The type of access granted for a file or directory

Personally identifiable information (PII): Any information used to infer an individual’s identity

Phishing: The use of digital communications to trick people into revealing sensitive data or deploying malicious software

Phishing kit: A collection of software tools needed to launch a phishing campaign

Physical attack: A security incident that affects not only digital but also physical environments where the incident is deployed

Physical social engineering: An attack in which a threat actor impersonates an employee, customer, or vendor to obtain unauthorized access to a physical location

Ping of death: A type of DoS attack caused when a hacker pings a system by sending it an oversized ICMP packet that is bigger than 64KB

Playbook: A manual that provides details about any operational action

Policy: A set of rules that reduce risk and protect information

Port: A software-based location that organizes the sending and receiving of data between devices on a network

Port filtering: A firewall function that blocks or allows certain port numbers to limit unwanted communication

Post-incident activity: The process of reviewing an incident to identify areas for improvement during incident handling

Potentially unwanted application (PUA): A type of unwanted software that is bundled in with legitimate programs which might display ads, cause device slowdown, or install other software

Private data: Information that should be kept from the public

Prepare: The first step of the NIST RMF related to activities that are necessary to manage security and privacy risks before a breach occurs

Prepared statement: A coding technique that executes SQL statements before passing them on to a database

Primary key: A column where every row has a unique entry

Principle of least privilege: The concept of granting only the minimal access and authorization required to complete a task or function

Privacy protection: The act of safeguarding personal information from unauthorized use

Procedures: Step-by-step instructions to perform a specific security task

Process of Attack Simulation and Threat Analysis (PASTA): A popular threat modeling framework that’s used across many industries

Programming: A process that can be used to create a specific set of instructions for a computer to execute tasks

Protect: A NIST core function used to protect an organization through the implementation of policies, procedures, training, and tools that help mitigate cybersecurity threats

Protected health information (PHI): Information that relates to the past, present, or future physical or mental health or condition of an individual

Protecting and preserving evidence: The process of properly working with fragile and volatile digital evidence

Proxy server: A server that fulfills the requests of its clients by forwarding them to other servers

Public data: Data that is already accessible to the public and poses a minimal risk to the organization if viewed or shared by others

Public key infrastructure (PKI): An encryption framework that secures the exchange of online information

Python Standard Library: An extensive collection of Python code that often comes packaged with Python


Query: A request for data from a database table or a combination of tables

Quid pro quo: A type of baiting used to trick someone into believing that they’ll be rewarded in return for sharing access, information, or money


Rainbow table: A file of pre-generated hash values and their associated plaintext

Random Access Memory (RAM): A hardware component used for short-term memory

Ransomware: A malicious attack where threat actors encrypt an organization’s data and demand payment to restore access

Rapport: A friendly relationship in which the people involved understand each other’s ideas and communicate well with each other

Recover: A NIST core function related to returning affected systems back to normal operation

Recovery: The process of returning affected systems back to normal operations

Red Hat® Enterprise Linux® (also referred to simply as Red Hat in this course): A subscription-based distribution of Linux built for enterprise use

Reflected XSS attack: An instance when malicious script is sent to a server and activated during the server’s response

Regular expression (regex): A sequence of characters that forms a pattern

Regulations: Rules set by a government or other authority to control the way something is done

Relational database: A structured database containing tables that are related to each other

Relative file path: A file path that starts from the user’s current directory

Replay attack: A network attack performed when a malicious actor intercepts a data packet in transit and delays it or repeats it at another time

Resiliency: The ability to prepare for, respond to, and recover from disruptions

Respond: A NIST core function related to making sure that the proper procedures are used to contain, neutralize, and analyze security incidents, and implement improvements to the security process

Restore:  The process of returning a system back to a state of normalcy. A restore or restoration process may involve formatting the main storage device before re-installing the operating system and applications as well as copying data from backups onto the reconstituted system.

Return statement: A Python statement that executes inside a function and sends information back to the function call

Reverse proxy server: A server that regulates and restricts the internet’s access to an internal server

Risk: Anything that can impact the confidentiality, integrity, or availability of an asset

Risk mitigation: The process of having the right procedures and rules in place to quickly reduce the impact of a risk like a breach

Root directory: The highest-level directory in Linux

Rootkit: Malware that provides remote, administrative access to a computer

Root user (or superuser): A user with elevated privileges to modify the system

Router: A network device that connects multiple networks together


Salting: An additional safeguard that’s used to strengthen hash functions

Sandboxing:  A means of isolating applications, code or entire operating systems in order to perform testing or evaluation. The sandbox limits the actions and resources available to the constrained item. This allows for the isolated item to be used for evaluation while preventing any harm or damage to be caused to the host system or related data or storage devices.

Scareware: Malware that employs tactics to frighten users into infecting their device

SCADA (Supervisory Control and Data Acquisition): A complex mechanism used to gather data and physical world metrics as well as perform measurement or management actions of the monitored systems for the purposes of automatic large complex real-world processes such as oil refining, nuclear power generation or water filtration. SCADA can provide automated control over very large complex systems whether concentrated in a single physical location or spread across long distances.

Search Processing Language (SPL): Splunk’s query language

Secure File Transfer Protocol (SFTP): A secure protocol used to transfer files from one device to another over a network

Secure shell (SSH): A security protocol used to create a shell with a remote system

Security architecture: A type of security design composed of multiple components, such as tools and processes, that are used to protect an organization from risks and external threats

Security audit: A review of an organization’s security controls, policies, and procedures against a set of expectations

Security controls: Safeguards designed to reduce specific security risks

Security ethics: Guidelines for making appropriate decisions as a security professional

Security frameworks: Guidelines used for building plans to help mitigate risk and threats to data and privacy

Security governance: Practices that help support, define, and direct security efforts of an organization

Security hardening: The process of strengthening a system to reduce its vulnerabilities and attack surface

Security information and event management (SIEM): An application that collects and analyzes log data to monitor critical activities in an organization

Security mindset: The ability to evaluate risk and constantly seek out and identify the potential or actual breach of a system, application, or data

Security operations center (SOC): An organizational unit dedicated to monitoring networks, systems, and devices for security threats or attacks

Security orchestration, automation, and response (SOAR): A collection of applications, tools, and workflows that use automation to respond to security events

Security posture: An organization’s ability to manage its defense of critical assets and data and react to change

Security zone: A segment of a company’s network that protects the internal network from the internet

Select: The third step of the NIST RMF that means to choose, customize, and capture documentation of the controls that protect an organization

Sensitive data: A type of data that includes personally identifiable information (PII), sensitive personally identifiable information (SPII), or protected health information (PHI)

Sensitive personally identifiable information (SPII): A specific type of PII that falls under stricter handling guidelines

Separation of duties: The principle that users should not be given levels of authorization that would allow them to misuse a system

Session: a sequence of network HTTP requests and responses associated with the same user

Session cookie: A token that websites use to validate a session and determine how long that session should last

Session hijacking: An event when attackers obtain a legitimate user’s session ID

Session ID: A unique token that identifies a user and their device while accessing a system

Set data: Data that consists of an unordered collection of unique values

Shared responsibility: The idea that all individuals within an organization take an active role in lowering risk and maintaining both physical and virtual security

Shell: The command-line interpreter

SIEM (Security Information and Event Management): A formal process by which the security of an organization is monitored and evaluated on a constant basis. SIEM helps to automatically identify systems that are out of compliance with the security policy as well as to notify the IRT (Incident Response Team) of any security violating events.

Signature: A pattern that is associated with malicious activity

Signature analysis: A detection method used to find events of interest

Simple Network Management Protocol (SNMP): A network protocol used for monitoring and managing devices on a network

Single sign-on (SSO): A technology that combines several different logins into one

Smishing: The use of text messages to trick users to obtain sensitive information or to impersonate a known source

Smurf attack: A network attack performed when an attacker sniffs an authorized user’s IP address and floods it with ICMP packets

Social engineering: A manipulation technique that exploits human error to gain private information, access, or valuables

Social media phishing: A type of attack where a threat actor collects detailed information about their target on social media sites before initiating the attack

SPAM:  A form of unwanted or unsolicited messages or communications typically received via e-mail but also occurring through text messaging, social networks or VoIP. Most SPAM is advertising, but some may include malicious code, malicious hyperlinks or malicious attachments.

Spear phishing: A malicious email attack targeting a specific user or group of users, appearing to originate from a trusted source

Speed: The rate at which a device sends and receives data, measured by bits per second

Splunk Cloud: A cloud-hosted tool used to collect, search, and monitor log data

Splunk Enterprise: A self-hosted tool used to retain, analyze, and search an organization’s log data to provide security information and alerts in real-time

Spyware: Malware that’s used to gather and sell information without consent

SQL (Structured Query Language): A programming language used to create, interact with, and request information from a database

SQL injection: An attack that executes unexpected queries on a database

Stakeholder: An individual or group that has an interest in any decision or activity of an organization

Standard error: An error message returned by the OS through the shell

Standard input: Information received by the OS via the command line

Standard output: Information returned by the OS through the shell

Standards: References that inform how to set policies

STAR method: An interview technique used to answer behavioral and situational questions

Stateful: A class of firewall that keeps track of information passing through it and proactively filters out threats

Stateless: A class of firewall that operates based on predefined rules and that does not keep track of information from data packets

Stored XSS attack: An instance when malicious script is injected directly on the server

String concatenation: The process of joining two strings together

String data: Data consisting of an ordered sequence of characters

Style guide: A manual that informs the writing, formatting, and design of documents

Subnetting: The subdivision of a network into logical groups called subnets

Substring: A continuous sequence of characters within a string

Sudo: A command that temporarily grants elevated permissions to specific users

Supply-chain attack: An attack that targets systems, applications, hardware, and/or software to locate a vulnerability where malware can be deployed

Suricata: An open-source intrusion detection system, intrusion prevention system, and network analysis tool

Switch: A device that makes connections between specific devices on a network by sending and receiving data between them

Symmetric encryption: The use of a single secret key to exchange information

Synchronize (SYN) flood attack: A type of DoS attack that simulates a TCP/IP connection and floods a server with SYN packets

Syntax: The rules that determine what is correctly structured in a computing language

Syntax error: An error that involves invalid usage of a programming language


Tailgating: A social engineering tactic in which unauthorized people follow an authorized person into a restricted area

TCP/IP model: A framework used to visualize how data is organized and transmitted across a network

tcpdump: A command-line network protocol analyzer

Technical skills: Skills that require knowledge of specific tools, procedures, and policies

Telemetry: The collection and transmission of data for analysis

Threat: Any circumstance or event that can negatively impact assets

Threat actor: Any person or group who presents a security risk

Threat assessment:  The process of evaluating the actions, events and behaviors that can cause harm to an asset or organization. Threat assessment is an element of risk assessment and management.

Threat hunting: The proactive search for threats on a network

Threat intelligence: Evidence-based threat information that provides context about existing or emerging threats

Threat modeling: The process of identifying assets, their vulnerabilities, and how each is exposed to threats

Transferable skills: Skills from other areas that can apply to different careers

Transmission Control Protocol (TCP): An internet communication protocol that allows two devices to form a connection and stream data

Triage: The prioritizing of incidents according to their level of importance or urgency

Trojan horse: Malware that looks like a legitimate file or program

True negative: A state where there is no detection of malicious activity

True positive An alert that correctly detects the presence of an attack

Tuple data: Data that consists of a collection of data that cannot be changed

Two-factor authentication:  The means of proving identity using two authentication factors usually considered stronger than any single factor authentication. A form of multi-factor authentication. Valid factors for authentication include Type 1: Something you know such as passwords and PINs; Type 2: Something you have such as smart cards or OTP (One Time Password) devices; and Type 3: Someone you are such as fingerprints or retina scans (aka biometrics).

Two-step authentication :  A means of authentication commonly employed on websites as an improvement over single factor authentication but not as robust as two-factor authentication. This form of authentication requires the visitor provide their username (i.e. claim an identity) and password (i.e. the single factor authentication) before performing an additional step. The additional step could be receiving a text message with a code, then typing that code back into the website for confirmation. Alternatives include receiving an e-mail and needing to click on a link in the message for confirmation, or viewing a pre-selected image and statement before typing in another password or PIN. Two-step is not as secure as two-factor because the system provides one of the factors to the user at the time of logon rather than requiring that the user provide both.

Type error: An error that results from using the wrong data type


Ubuntu: An open-source, user-friendly distribution that is widely used in security and other industries

Unauthorized access: An incident type that occurs when an individual gains digital or physical access to a system or application without permission

Uncontrolled zone: Any network outside your organization’s control

Unified Extensible Firmware Interface (UEFI): A microchip that contains loading instructions for the computer and replaces BIOS on more modern systems

USB baiting: An attack in which a threat actor strategically leaves a malware USB stick for an employee to find and install to unknowingly infect a network

User: The person interacting with a computer

User Datagram Protocol (UDP): A connectionless protocol that does not establish a connection between devices before transmissions

User-defined function: A function that programmers design for their specific needs

User interface: A program that allows the user to control the functions of the operating system

User provisioning: The process of creating and maintaining a user’s digital identity


Variable: A container that stores data

Virtual Private Network (VPN): A network security service that changes your public IP address and hides your virtual location so that you can keep your data private when you are using a public network like the internet

Virus: Malicious code written to interfere with computer operations and cause damage to data and software

VirusTotal: A service that allows anyone to analyze suspicious files, domains, URLs, and IP addresses for malicious content

Vishing: The exploitation of electronic voice communication to obtain sensitive information or to impersonate a known source

Visual dashboard: A way of displaying various types of data quickly in one place

Vulnerability: A weakness that can be exploited by a threat

Vulnerability assessment: The internal review process of an organization’s security systems

Vulnerability management: The process of finding and patching vulnerabilities

Vulnerability scanner: Software that automatically compares existing common vulnerabilities and exposures against the technologies on the network


Watering hole attack: A type of attack when a threat actor compromises a website frequently visited by a specific group of users

Web-based exploits: Malicious code or behavior that’s used to take advantage of coding flaws in a web application

Whitelist: A security mechanism prohibiting the execution of any program that is not on a pre-approved list of software. The whitelist is often a list of the file name, path, file size and hash value of the approved software. Any code that is not on the list, whether benign or malicious, will not be able to execute on the protected system.

Whaling: A category of spear phishing attempts that are aimed at high-ranking executives in an organization

Wide Area Network (WAN): A network that spans a large geographic area like a city, state, or country

Wi-Fi Protected Access (WPA): A wireless security protocol for devices to connect to the internet

Wildcard: A special character that can be substituted with any other character

Wireshark: An open-source network protocol analyzer

World-writable file: A file that can be altered by anyone in the world

Worm: Malware that can duplicate and spread itself across systems on its own



YARA-L: A computer language used to create rules for searching through ingested log data


Zero-day: An exploit that was previously unknown

Zombie: A term related to the malicious concept of a botnet. The term zombie can be used to refer to the system that is host to the malware agent of the botnet or to the malware agent itself. If the former, the zombie is the system that is blinding performing tasks based on instructions from an external and remote hacker. If the latter, the zombie is the tool that is performing malicious actions such as DoS flooding, SPAM transmission, eavesdropping on VoIP calls or falsifying DNS resolutions as one member of a botnet.