Use this cheat sheet as a quick look-up when you encounter an unfamiliar abbreviation. Entries are grouped by category for easier navigation.

Attacks & Vulnerabilities

AcronymFull NameDescription
CVECommon Vulnerabilities and ExposuresStandardized identifier for publicly disclosed security vulnerabilities
CSRFCross-Site Request ForgeryAttack that tricks a user’s browser into making unintended requests
DoSDenial of ServiceAttack that makes a service or network unavailable
IDORInsecure Direct Object ReferencesWeb flaw where access control on object references is missing
RCERemote Code ExecutionVulnerability allowing an attacker to run arbitrary code remotely
SMBGhostCritical SMBv3 vulnerability (CVE-2020-0796)
SQLiSQL InjectionAttack that injects malicious SQL into a query
SSRFServer-Side Request ForgeryAttack that causes the server to make requests on the attacker’s behalf
TOCTOUTime-Of-Check-To-Time-Of-UseRace-condition vulnerability class
XSSCross-Site ScriptingAttack that injects malicious scripts into web pages viewed by other users
A08OWASP Top 10 – A08Software & Data Integrity Failures category in the OWASP Top 10

Defense & Controls

AcronymFull NameDescription
ACLAccess Control ListList defining which users/systems have which permissions
AESAdvanced Encryption StandardSymmetric encryption algorithm widely used today
ASLRAddress Space Layout RandomizationMemory protection that randomizes process memory locations
DACDiscretionary Access ControlAccess control where the resource owner sets permissions
DEP / NXData Execution Prevention / No-ExecutePrevents code execution in data memory regions
FIMFile Integrity MonitoringDetects unauthorized changes to files
MFAMulti-Factor AuthenticationAuthentication requiring two or more independent factors
SELinuxSecurity-Enhanced LinuxLinux kernel security module enforcing mandatory access control
SUID / SGIDSet User ID / Set Group IDUnix permission bits that run a file with the owner’s privileges
TCBTrusted Computing BaseSet of hardware/software critical to a system’s security
VPNVirtual Private NetworkEncrypted tunnel protecting traffic over an untrusted network
WAFWeb Application FirewallFilters malicious HTTP traffic before it reaches an application
ZTAZero Trust Architecture”Never trust, always verify” security model
CSPContent Security PolicyHTTP header that restricts resources a browser can load
HMACHash-based Message Authentication CodeCryptographic MAC using a hash function and secret key
SHA-256Secure Hash Algorithm 256-bitCryptographic hash function producing a 256-bit digest
SSLSecure Sockets LayerPredecessor to TLS; largely deprecated
TLSTransport Layer SecurityCryptographic protocol securing communications over a network

Networking

AcronymFull NameDescription
ARPAddress Resolution ProtocolMaps IP addresses to MAC addresses on a local network
ASAutonomous SystemIndependently administered network on the Internet
BGPBorder Gateway ProtocolRouting protocol used between autonomous systems on the Internet
DHCPDynamic Host Configuration ProtocolAutomatically assigns IP addresses to devices on a network
DNSDomain Name SystemTranslates domain names to IP addresses
FTPFile Transfer ProtocolProtocol for transferring files between hosts
HTTPHypertext Transfer ProtocolCore application-layer protocol of the web
HTTPSHypertext Transfer Protocol SecureHTTP protected by TLS
ICMPInternet Control Message ProtocolUsed for diagnostic messages (e.g., ping)
IPInternet ProtocolNetwork-layer protocol for packet delivery
IPv4Internet Protocol version 432-bit IP addressing scheme
LANLocal Area NetworkNetwork covering a limited area (home, office, campus)
MACMedia Access ControlHardware address of a network interface
NATNetwork Address TranslationRewrites private IP addresses to public ones at a router
NFCNear Field CommunicationShort-range wireless communication standard
P2PPeer-to-PeerNetwork architecture without a central server
PSTNPublic Switched Telephone NetworkTraditional circuit-switched telephone infrastructure
RFIDRadio-Frequency IdentificationTechnology using radio waves to identify tags/objects
SMTPSimple Mail Transfer ProtocolProtocol for sending email
SSHSecure ShellProtocol for secure remote login and command execution
STUNSession Traversal Utilities for NATProtocol to discover public IP/port behind a NAT
TCPTransmission Control ProtocolConnection-oriented, reliable transport protocol
TCP/IPTransmission Control Protocol / Internet ProtocolCore protocol suite of the Internet
TorThe Onion RouterAnonymity network routing traffic through multiple relays
TTLTime To LiveLimits the lifespan of data in a network or cache
UDPUser Datagram ProtocolConnectionless, low-latency transport protocol
UPnPUniversal Plug and PlayProtocol for automatic network device discovery
WANWide Area NetworkNetwork spanning large geographic areas

Authentication & Identity

AcronymFull NameDescription
DKIMDomainKeys Identified MailEmail authentication via cryptographic signatures
DMARCDomain-based Message Authentication, Reporting and ConformanceEmail policy framework combining SPF and DKIM
JWTJSON Web TokenCompact, URL-safe token for transmitting claims
OAuth 2.0Open Authorization 2.0Authorization framework for delegated access
PIIPersonally Identifiable InformationData that can identify a specific individual
SPFSender Policy FrameworkEmail authentication specifying authorized mail senders
SSNSocial Security NumberU.S. government-issued personal identifier

Web & Application Security

AcronymFull NameDescription
APIApplication Programming InterfaceInterface for programmatic interaction between systems
BOLABroken Object Level AuthorizationAPI equivalent of IDOR; missing authorization on object access
CRUDCreate, Read, Update, DeleteStandard set of data operations
DOMDocument Object ModelBrowser’s tree representation of an HTML document
GraphQLGraph Query LanguageQuery language and runtime for APIs
OWASPOpen Web Application Security ProjectNon-profit focused on web application security
OWASP ZAPOWASP Zed Attack ProxyOpen-source web application security scanner
RESTRepresentational State TransferArchitectural style for distributed hypermedia systems

Operating Systems & Platforms

AcronymFull NameDescription
BIOSBasic Input/Output SystemFirmware initializing hardware at boot
CLICommand-Line InterfaceText-based interface for interacting with a system
GNU”GNU’s Not Unix”Unix-compatible free software project
GUIGraphical User InterfaceVisual interface using windows, icons, and menus
HALHardware Abstraction LayerSoftware layer between hardware and the OS
KVMKernel-based Virtual MachineLinux virtualization module
MMUMemory Management UnitHardware component managing virtual-to-physical memory mapping
OSOperating SystemSoftware managing hardware resources and providing services
POSIXPortable Operating System InterfaceUnix compatibility standard
RTOSReal-Time Operating SystemOS designed for time-critical applications
SELinuxSecurity-Enhanced LinuxMandatory access control framework for Linux
SUID / SGIDSet User ID / Set Group IDUnix permission bits that run a file with elevated privileges
VMVirtual MachineSoftware emulation of a physical computer
VMMVirtual Machine MonitorSoftware layer managing virtual machines (a.k.a. Hypervisor)
WSLWindows Subsystem for LinuxCompatibility layer running Linux binaries on Windows

Cloud & Infrastructure

AcronymFull NameDescription
AWSAmazon Web ServicesAmazon’s cloud computing platform
EC2Elastic Compute CloudAWS virtual server service
IaaSInfrastructure as a ServiceCloud model providing virtualized compute resources
ICSIndustrial Control SystemsSystems controlling industrial processes and infrastructure
ISPInternet Service ProviderCompany providing Internet connectivity
IX / IXPInternet Exchange / Internet Exchange PointPhysical infrastructure where networks exchange traffic
MSPManaged Service ProviderCompany managing IT services on behalf of clients

Intelligence & Monitoring

AcronymFull NameDescription
EXIFExchangeable Image File FormatMetadata embedded in image files (location, device, time)
OSINTOpen Source IntelligenceIntelligence gathered from publicly available sources
RTTRound-Trip TimeTime for a packet to travel to a destination and back

Shell & CLI Commands

Acronym / CommandFull NameDescription
cpcopyCopies files or directories
dfDisk FreeShows available disk space
dirbDirectory brute-forcerWeb content scanner for hidden directories
duDisk UsageShows disk space used by files/directories
mvmoveMoves or renames files
ncnetcatReads/writes data across network connections
nmapNetwork MapperNetwork discovery and security auditing tool
NSEnmap Scripting EngineNmap’s built-in scripting framework
psprocess statusLists running processes
pwdPrint Working DirectoryShows the current directory path
rmremoveDeletes files or directories
sedstream editorFilters and transforms text streams
sudosuperuser doRuns a command with elevated (root) privileges
tarTape ARchiveCreates and extracts archive files
trtranslateTranslates or deletes characters in a stream
BashBourne Again SHellDefault shell on most Linux distributions
ZshZ ShellExtended Bourne shell with many improvements

Miscellaneous

AcronymFull NameDescription
ASCIIAmerican Standard Code for Information Interchange7-bit character encoding standard
CTFCapture The FlagCybersecurity competition format
GDPRGeneral Data Protection RegulationEU data privacy regulation
HITLHuman in the LoopAI safety pattern requiring human review of decisions
LLMLarge Language ModelAI model trained on large text corpora
NVDNational Vulnerability DatabaseU.S. government database of known vulnerabilities
UUIDUniversally Unique Identifier128-bit identifier designed to be globally unique
UTF-8Unicode Transformation Format, 8-bitVariable-width character encoding for Unicode