Domain 4: Communication and Network Security Flashcards
Acknowledgment (ACK)
An acknowledgment of a signal being received.
Address Resolution Protocol (ARP)
Used at the Media Access Control (MAC) layer to provide for direct communication between two devices within the same LAN segment.
Advanced Persistent Threat (APT)
An adversary with sophisticated levels of expertise and significant resources who is able to use multiple different attack vectors (e.g., cyber, physical, and deception) to achieve its objectives. These are typically to establish and extend footholds within the organization’s IT infrastructure to continually exfiltrate information; undermine or impede critical aspects of a mission, program, or organization; or place itself in a position to do so in the future. Moreover, the APT pursues its objectives repeatedly over an extended period, adapting to a defender’s efforts to resist it, and with determination to maintain the level of interaction needed to execute its objectives.
Application Programming Interface (API) Object Notation (JSON).
- Mobile code mechanisms that provide ways for applications to share data, methods, or functions over a network. Usually implemented either in XML or JavaScript 2. A reference to a software access point or library function with a well-defined syntax and welldefined functionality.
Bandwidth
The amount of information transmitted over time. A process consisting of learning or education could necessitate higher bandwidth than a quick status update, which would require a lower bandwidth.
Bit
Most essential representation of data (zero or one) at Layer 1 of the OSI 7-Layer Model.
Bluetooth (Wireless Personal Area Network IEEE 802.15)
Bluetooth wireless technology is an open standard for short-range RF communication used primarily to establish wireless personal area networks (WPANs). It has been integrated into many types of business and consumer devices.
Bound Network
Network in which devices are connected at Layer 1 by means of physical cables, wires or fiber. Often referred to as wired networks or Ethernet networks or by wiring or cable standard used, (e.g., fiber network, Cat 5, or Cat 6 network). See also Unbound (wireless) Network(s).
physically bound
Boundary Routers
Primarily advertise routes that external hosts can use to reach internal ones.
Bridges
A device that creates a single aggregate network from separate network segments. Using the OSI model, this device aggregates networks at Layer 2.
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
A method of flow control in a network. To prevent more than one station from accessing the network simultaneously, the sending station announces its intent to send, and other stations wait until the sending station announces its completion.
Cellular Network
A radio network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station.
Circuit-Switched Network
A network that establishes a dedicated circuit between endpoints.
Code-Division Multiple Access (CDMA)
Every call’s data is encoded with a unique key, then the calls are all transmitted at once.
Concentrators
Multiplex connected devices into one signal to be transmitted on a network.
Content Distribution Network (CDN)
A large, distributed system of servers deployed in multiple data centers, which moves content to achieve QoS and availability requirements.
Control Plane
Control of network functionality and programmability is directly made to devices at this layer. OpenFlow was the original framework/protocol specified to interface with devices through southbound interfaces.
Converged Protocols
A protocol that combines or converges standard protocols such as TCP/IP with proprietary or other nonstandard protocols. These can sometimes provide greatly enhanced functionality and security to meet the needs of specific situations or industries. Adopting them can also complicate enterprise-wide security engineering efforts by requiring additional specialist knowledge and skills to manage and secure.
Domain Name Service (DNS)
This acronym can be applied to three interrelated elements: a service, a physical server, and a network protocol.
Translates friendly-names into IP addresses that can then be routed using Address resolution protocol.
Driver (Device Driver)
Software layer that provides an interface for accessing the functions of hardware devices. Typically used by the OS.
Dynamic Host Configuration Protocol (DHCP)
An industry standard protocol used to dynamically assign IP addresses to network devices.
Dynamic or Private Ports
Ports 49152– 65535. Whenever a service is requested that is associated with well-known or registered ports, those services will respond with a dynamic port.
East-West Data Flow (or Traffic)
Network data traffic that flows laterally across a set of internal systems, networks, or subnetworks within an IT architecture. These can flow within a data center or between geographically dispersed locations. Contrast with north-south data flows, in which northbound data is leaving the organization and southbound data is entering it.
Fiber Distributed Data Interface (FDDI)
A LAN standard, defined by ANSI X3T9.5, specifying a 100 Mbps token-passing network using fiber- optic cable, with transmission distances of up to two kilometers.
Fibre Channel over Ethernet (FCoE)
A lightweight encapsulation protocol that lacks the reliable data transport of the TCP layer.
File Transfer Protocol (FTP)
The internet protocol (and program) used to transfer files between hosts.
Firewalls
Devices that enforce administrative security policies by filtering incoming traffic based on a set of rules.
Firmware
Computer programs and data stored in hardware typically in read-only memory (ROM) or programmable read-only memory (PROM)— such that the programs and data cannot be dynamically written or modified during execution of the programs.
Frame
Data represented at Layer 2 of the OSI 7-Layer Model.
Gateway Device
A firewall or other device sitting at the edge of a network to regulate traffic and enforce rules.
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 HTML pages to the client browser. The protocol used to transport hypertext files across the Internet.
Internet Control Message Protocol (ICMP)
An IP network protocol standardized by the IETF through RFC 792 to determine whether a particular service or host is available.
Internet Group Management Protocol (IGMP)
Used to manage multicasting groups that are a set of hosts anywhere on a network listening for a transmission.
Internet of Things (IoT)
A virtual network made up of small, dedicated-use devices that are typically designed as small form factor, embedded hardware with a limited functionality OS. They may interface with the physical world and tend to be pervasively deployed where they exist.
Internet Protocol (IPv4)
The dominant protocol that operates at Layer 3 of the OSI 7-Layer Model. IP is responsible for addressing packets so that they can be transmitted from the source to the destination hosts.
Internet Protocol (IPv6)
A modernization of IPv4 that includes a much larger address field: IPv6 addresses are 128 bits that support 2128 hosts.
Internetworking
Two different sets of servers and communications elements using network protocol stacks to communicate with each other and coordinate their activities with each other.
Kill Chain, Cyber Kill Chain
A generalized attack model consisting of actions on the objective and six broad, overlapping sets of operational activities: reconnaissance, weaponization, delivery, exploitation, installation, and command and control. APT actors often combine these operations in complex ways to achieve their goals; such attacks may span many months. For defenders, the kill chain model highlights the temporary gain in security that can result by improved systems and organizational hardening across any or all these areas.
Lightweight Directory Access Protocol (LDAP)
Authentication is specified as simple (basic), simple using SSL/TLS, or Simple Authentication and Security Layer (SASL).
Logical Link Control (LLC)
One of two sublayers that together make up the data link layer in the OSI.
Man-in-the-Middle (MITM)
A form of active attack in which the attacker inserts themselves into the physical or logical communications flow between two parties and falsifies or alters data exchanged as the attacker chooses to. Machine- in-the-browser (MITB) attacks focus on Layer 7 vulnerabilities to masquerade as client to the server and as server to the client.
Media Access Control (MAC)
The 48-bit hex number assigned to all network cards. The first 24 bits are assigned to the card manufacturer with the send being a unique value (address) for that card.
Microsegmented Networks, Microsegmentation
Part of a zero trust strategy that breaks LANs into small, highly localized zones using firewalls or similar technologies. At the limit, this places a firewall at every connection point.
Modem
Provides modulation and demodulation of binary data into analog signals for transmission through telephone, cable, fiber, or other signaling systems.
Multiprotocol Label Switching (MPLS)
A WAN protocol that operates at both Layer 2 and Layer 3 and does label switching.
Network Function Virtualization (NFV)
Alternately referred to as virtual network function. The objective of NFV is to decouple functions, such as firewall management, intrusion detection, NAT, and name service resolution, away from specific hardware implementation and move them into software solutions. NFV’s focus is to optimize distinct network services.
Network Management
Monitors network performance and identifies attacks and failures. Mechanisms include components that enable network administrators to monitor and restrict resource access.
North-South Network Data Flow (or Traffic)
- Data flowing either from the organization to external destinations (northbound) or into the organization from external sources (southbound). 2. In SDN terms, data flowing up (northbound) or down (southbound) the stack of data/control/applications planes.
Open Shortest Path First (OSPF)
An interior gateway routing protocol developed for IP networks based on the shortest path first or link-state algorithm.
OSI Layer 1
Physical Layer. converts a frame into bits for transmission over the physical connection medium.
OSI Layer 2
Data Link Layer. It is the layer where media access control (MAC) addresses reside and frames are transmitted
OSI Layer 3
Network Layer. h is responsible for logical addressing and translating logical names into physical addresses. This layer also controls the routing of data from source to destination as well as the building and dismantling of packets.
IP Addresses
OSI Layer 4
Transport Layer. It’s responsible for checking that data packets created in the Session layer are received error- free. If necessary, it also changes the length of messages for transport up or down the remaining layers
TCP, UDP, TLS
OSI Layer 5
Session Layer. It determines how two computers establish, use, and end a session. Security authentication and network- naming functions required for applications occur here.
OSI Layer 6
Presentation Layer. is responsible for formatting data exchange, such as graphic commands, and converting character sets.
it presents data
OSI Layer 7
Application Layer.
This layer deals with how applications access the network and describes application functionality, such as file transfers, messaging, and so on
Packet
Representation of data at Layer 3 of the OSI 7-Layer Model.
Packet Loss
Degradation of VoIP or other streaming data caused by lost packets. A technique called packet loss concealment (PLC) is used in VoIP communications to mask the effect of dropped packets.
Packet-Switched Networks
Networks that do not use a dedicated connection betweenendpoints.
Peering
A voluntary interconnection of administratively separate networks to exchange traffic.
Point-to-Point Protocol (PPP)
Provides a standard method for transporting multiprotocol datagrams over point-to-point links.
Port Address Translation (PAT)
An extension to network address translation (NAT) to translate all addresses to one routable IP address and translate the source port number in the packet to a unique value.
Quality of Service (QoS)
Refers to the capability of a network to provide better service to selected network traffic over various technologies, including frame relay, ATM, Ethernet and 802.1 networks, SONET, and IP-routed networks that may use any or all these underlying technologies.
Registered Ports
Ports 1024–49151. These ports typically accompany nonsystem applications associated with vendors and developers.
Remote Procedure Call (RPC)
A protocol that enables one system to execute instructions on other hosts across a network infrastructure.
Root of Trust (RoT)
Hardware-based mechanisms that guarantee the integrity of the hardware prior to loading the OS of a computer.
Segment
- Data representation (or datagram name) at Layer 4 of the OSI 7-Layer Model. 2. A portion of a larger network, usually isolated by firewalls or routers at either end from other portions of the network. See also Microsegmented Networks, Microsegmentation.
Simple Network Management Protocol (SNMP)
An IP protocol for collecting and organizing information about managed devices on IP networks. It can be used to determine the “health” of networking devices including routers, switches, servers, workstations, printers, and modem racks.
Smurf
ICMP echo request sent to the network broadcast address of a spoofed victim causing all nodes to respond to the victim with an echo reply.
Software-Defined Networking (SDN)
Any of a broad range of techniques that enable network management, routing, forwarding, and control functions to be directed by software. This is generally done by abstracting the control and management planes from the data plane and its forwarding functions.
Software-Defined Wide Area Network (SD-WAN)
An extension of the SDN practices to connect to entities spread across the internet to support WAN architecture especially related to cloud migration.
Terminal Emulation Protocol (Telnet)
A command-line protocol designed to give command-line access from one host to another.
Transmission Control Protocol (TCP)
The major transport protocol in the internet suite of protocols that provides reliable, connection- oriented, full-duplex streams.
Transmission Control Protocol over Internet Protocol (TCP/IP)
The name of the IETF’s four-layer networking model, and its protocol stack.
Transport Control Protocol/Internet Protocol (TCP/ IP) Model
Internetworking protocol model created by the IETF, which specifies four layers of functionality: link layer (physical communications), internet layer (network-to- network communication), transport layer (basic channels for connections and connectionless exchange of data between hosts), and application layer, where other protocols and user applications programs make use of network services.
Trusted Platform Module (TPM)
A tamper-resistant integrated circuit built into some computer motherboards that can perform cryptographic operations (including key generation) and protect small amounts of sensitive information, such as passwords and cryptographic keys.
Unbound (Wireless) Network(s)
Network in which physical layer interconnections are done using radio, light, or other means not confined to wires, cables, or fibers. Devices on unbound networks may or may not be mobile. See also Bound Networks.
Virtual Local Area Networks (VLANs)
Allow network administrators to use switches to create software-based LAN segments that can be defined based on factors other than physical location.
Voice over Internet Protocol (VoIP)
A set of technologies that enables voice to be sent over a packet network.
Web Application Firewall (WAF)
A software-based firewall, which monitors and filters exchanges between an applications program and a host. WAFs usually involve inspection and filtering of HTTP and HTTPS conversations.
Wi-Fi (Wireless LAN IEEE 802.11x)
Primarily associated with computer networking, Wi-Fi uses the IEEE 802.11x specification to create a wireless LAN either public or private.
WiMAX (Broadband Wireless Access IEEE 802.16)
A well-known example of wireless broadband. WiMAX can potentially deliver data rates of more than 30 Mbps.
Zero Trust Model/ Architecture
Replaces trust, but verify as security design principle by asserting that all activities attempted, by all users or entities, must be subject to control, authentication, authorization, and management at the most granular level possible. NIST and others have proposed zero trust architectures as guidance frameworks for organizations to use as they combine microsegmentation, access control, behavior modeling, and threat intelligence (among other techniques) in moving toward a zero trust implementation.
Open Systems Interconnection (OSI) model
A standardized reference model defined by ISO to categorize the process of communication between computers in terms of seven layers.
deencapsulation
The process of stripping a layer’s header and footer from a protocol data unit (PDU) as it travels up the OSI model layers.
encapsulation
The act of enclosing or encasing one item inside another. Commonly used to describe tunneling, in which one protocol is enclosed in another or, in the context of the Open Systems Interconnection (OSI) model, each layer’s content is encapsulated as the payload in the next- lower layer and a header is added. The inverse of encapsulation is de- encapsulation.
peer layer communication
Within the OSI model, the information removed by each layer contains instructions, checksums, and so on that can be understood only by the peer layer that originally added or created the information.
protocol data unit (PDU)
The name of the network container at OSI layers 7, 6, and 5 (Application, Presentation, and Session).
Goes on to segments/datagrams, packets, frames, bits in lower layers
Protocol Analyzer
A physical device that listens in on (sniffs) network traffic and looks for items it can make sense of. There is a legitimate purpose for these devices: administrators use them to analyze traffic. However, when they’re used by sources other than the administrator, they become security risks. Aka protocol analyzer, network evaluator, network analyzer, traffic monitor, or packet capturing utility.
Telnet
A protocol that functions at the Application layer of the OSI model, providing terminal- emulation capabilities. Telnet has been deprecated in favor of Secure Shell (SSH)
Trivial File Transfer Protocol (TFTP)
A protocol similar to FTP that doesn’t provide the security or error- checking features of FTP. This is a network application that supports an exchange of files that does not require authentication. Used to host network device configuration files and can support multicasting. TFTP should not be used since it operates in cleartext. See File Transfer Protocol (FTP).
File Transfer Protocol (FTP)
A protocol used over TCP/IP that permits the transferring of files between computer systems. Because FTP has been implemented on numerous types of computer systems, files can be transferred between disparate systems (for example, a personal computer and a minicomputer).
Simple Mail Transfer Protocol (SMTP)
The primary protocol used to transfer or send email messages from clients to servers and from server to server.
Simple Network Management Protocol (SNMP)
The management protocol created for sending information about the health of the network to network management consoles.
Internet Message Access Protocol (IMAP)
A protocol used to transfer email messages from an email server to an email client. Allows for messages to be saved or archived on the email server rather than the client (as is the limitation with Post Office Protocol [POP]).
Post Office Protocol (POP)
An email access program that can be used to retrieve email from an email server. POP results in archiving messages only on the client; they are fully removed from the server. See Internet Message Access Protocol (IMAP).
Dynamic Host Configuration Protocol (DHCP)
A protocol used to assign TCP/IP configuration settings to systems upon bootup, including TCP/IP addresses, default gateways, subnet masks, and DNS configurations. DHCP uses UDP port 67 for server point- to- point response and port 68 for client request broadcast. DHCP supports centralized control and management of network addressing.
Hypertext Transfer Protocol (HTTP)
The protocol used to transmit web page elements from a web server to web browsers (over the well- known service TCP/UDP port address 80).
Hypertext Transfer Protocol Secured (HTTPS)
The encrypted form of HTTP that currently uses TLS (previously used SSL) and mostly operates over TCP port 443.
Line Printer Daemon (LPD)
This is a network service that is used to spool print jobs and send print jobs to printers. port 515
X Window
A GUI API for command- line operating systems. Port 6000-6063
Network File System (NFS)
A protocol that enables users to access files on remote computers as if the files were local. TCP Port 2049
User Datagram Protocol (UDP)
A connectionless protocol located at layer 4 of the OSI model.