Glossary
Building your knowledge, one term at a time.
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MAC Flooding
MAC flooding is an attack on an Ethernet switch’s MAC address table (often called the CAM table). A switch learns which MAC addresses sit on which ports by reading the source address of incoming frames.…
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Malware
Malware is a collective term for malicious software created to disrupt normal computer operations, gather sensitive information, gain unauthorised access to systems or display unwanted advertising. It includes viruses which attach to other files to…
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Man-in-the-Middle (MITM)
A Man-in-the-Middle (MITM) attack is where a malicious actor intercepts communication between two parties without their knowledge. The attacker positions themselves between a user and a server to eavesdrop on messages or to alter data…
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Man-in-the-Mobile (MITMO)
Man-in-the-Mobile (MITMO) describes an attack in which malware on a smartphone secretly relays and modifies communications between mobile applications and their servers. It can intercept one time passcodes sent by text, inject unauthorised commands into…
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McCumber Cube
The McCumber Cube is a conceptual framework in information security developed by John McCumber in 1991. It provides guidance in establishing and evaluating security initiatives by considering three interrelated dimensions. The first dimension relates to…
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mDNS
Multicast DNS (mDNS) is a way for devices on the same local network to resolve hostnames and advertise services without using a central DNS server. It sends and listens for queries over UDP port 5353 to…
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Measured Boot
Measured Boot is a start-up process where each component that runs during boot is hashed and the results are recorded in the device’s Trusted Platform Module (TPM) registers, called PCRs. The chain begins with UEFI…
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Metasploit
Metasploit is an open-source penetration testing framework used to find, verify and demonstrate security weaknesses with permission. It is built around modules. Exploits trigger a specific vulnerability. Payloads are what runs if the exploit works, such as a command…
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Microsoft 365
Microsoft 365 is a cloud-based productivity and collaboration platform that includes Office applications, Exchange Online, SharePoint, Teams, OneDrive, and various security and compliance tools.
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Microsoft Exchange
Microsoft Exchange is an enterprise email and calendaring platform developed by Microsoft. It is available as an on-premises solution, Exchange Server, and as a cloud-based service, Exchange Online, which is included in Microsoft 365.
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MIME
Multipurpose Internet Mail Extensions (MIME) is a standard that tells software what type of data a message or file contains and how it is packaged. In email, MIME adds headers that describe each part of…
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Modem
A modem is a device that converts the digital signals used by computers into the analogue form required for transmission over phone lines, cable networks or radio links and vice versa. Its name comes from…
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MS-DOS
MS-DOS is a text based operating system for early IBM compatible PCs. It is 16 bit, single user and mostly single task. You work at a command prompt and run programs by typing their names…
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Multi-Factor Authentication (MFA)
Multi-Factor Authentication (MFA) means requiring two or more different forms of authentication before granting access. These forms fall into categories such as something you know (for example a password), something you have (for example a…
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Multicast
Multicast is the delivery of a single data stream from one sender to multiple selected receivers. Instead of creating a separate unicast session for each recipient, the sender transmits one copy of each packet which…
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Multiplexing
Multiplexing means carrying many independent signals over a single medium at the same time. It saves cost and increases link utilisation. Classic methods include Time Division Multiplexing, which gives each stream a timeslot, and Statistical…
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Neighbour Discovery
Neighbour Discovery is the IPv6 control mechanism that replaces ARP and provides critical link-local functions including address resolution, router and prefix discovery, default gateway selection, duplicate address detection, on-link determination and ongoing neighbour reachability checks;…
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NetBIOS
NetBIOS (Network Basic Input/Output System) is an old Windows networking interface that provides three core services: name registration and lookup, connection-oriented sessions, and connectionless datagrams. Early LANs used it for computers to find each other and…
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NetFlow
NetFlow is a protocol for gathering information about IP traffic that passes through a network device such as a router or switch. It records each flow, a unidirectional sequence of packets sharing the same source…
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Network Address Translation (NAT)
Network Address Translation, or NAT, is the technique routers use to rewrite IP addresses on packets as they pass between a private network and the wider internet. In a typical home setup all devices share…