IT glossary: technical terms explained simply.

3

3-2-1 rule

Backup rule: three copies, two media, one copy at another location. Learn more →

A

Active Directory

Microsoft's on-premises directory service that manages users, computers and groups and enables sign-in via Kerberos and LDAP. Learn more →

AI literacy

The ability to use AI systems properly and to assess opportunities and risks. A term from the EU AI Regulation. Learn more →

B

BSI

Federal Office for Information Security, Germany's cybersecurity authority.

C

CEO fraud

Fraud in which criminals pose as executives and demand urgent payments. Learn more →

CIS Benchmark

Recognised configuration guidance for setting up systems securely. Learn more →

Conditional access

Rules that allow, restrict or require MFA for access depending on user, device, location and risk. Learn more →

Configuration Manager (SCCM)

On-premises Microsoft solution for software distribution, operating system deployment and reporting. Learn more →

E

EU AI Act

Regulation (EU) 2024/1689 on artificial intelligence. It governs the use of AI on a risk basis and applies in stages. Learn more →

Extended Security Updates (ESU)

Paid security updates for Windows 10 after regular support ended. Learn more →

F

False self-employment

Formally self-employed work that is actually performed like an employment relationship. Learn more →

FIDO2 / passkeys

Phishing-resistant sign-in methods with security keys or devices instead of passwords. Learn more →

G

Group managed service account (gMSA)

Service account with an automatically managed long password that makes Kerberoasting harder.

H

Hallucination (AI)

A statement invented by an AI that sounds plausible but is not true. Results should therefore be checked. Learn more →

Hypervisor

Software that runs multiple virtual machines on one physical server. Learn more →

I

Immutable backup

A backup that cannot be changed or deleted for a defined period, not even by attackers. Learn more →

Inference

Running a trained AI model to compute an answer to an input, as opposed to training.

IT-Grundschutz

BSI methodology with modules and measures for an appropriate level of information security.

K

Kerberoasting

Attack in which tickets for service accounts are requested and cracked offline. Learn more →

Kerberos

Ticket-based network authentication protocol used in Active Directory.

L

Large language model (LLM)

A language model trained on very large amounts of text that can understand, summarise and write text. Examples are models from OpenAI, Anthropic, Google and open models. Learn more →

M

Microsoft Entra ID

Microsoft's cloud identity service (formerly Azure AD) for signing in to cloud applications such as Microsoft 365. Learn more →

Microsoft Intune

Microsoft cloud service for managing devices and applications. Learn more →

Multi-factor authentication (MFA)

Sign-in with at least two independent proofs, such as a password and an authenticator app. Learn more →

N

Nextcloud

Open-source platform for file storage, synchronisation, calendar and collaboration. Learn more →

NIS2

EU cybersecurity directive, in force in Germany since 6 December 2025 through the NIS2 implementation law. Learn more →

O

Ollama

Open-source software for running open language models locally on your own hardware or rented GPU servers. Learn more →

P

Patch management

Planned process for installing security updates promptly, tested and controlled. Learn more →

Phishing

Fraud attempt by email or message aiming to obtain credentials or payments. Learn more →

Power over Ethernet (PoE)

Powering devices such as access points over the network cable.

Principle of least privilege

Everyone receives only the rights necessary for their task. Learn more →

Privileged access management (PAM)

Control and monitoring of privileged accounts such as administrators, often with time-limited rights and a password vault. Learn more →

Prompt injection

An attack in which hidden instructions in texts or documents are meant to make an AI perform unintended actions. Learn more →

Proof of concept (PoC)

A small trial checking whether a solution works in your own environment. Learn more →

Proxmox VE

Open-source virtualisation platform for virtual machines and containers. Learn more →

R

Ransomware

Malware that encrypts data and demands a ransom for its release. Learn more →

Recovery point objective (RPO)

Maximum tolerable data loss, measured as time since the last backup. Learn more →

Recovery time objective (RTO)

Maximum tolerable time to restore a system after an outage. Learn more →

Reporting duty under Art. 33 GDPR

Duty to report personal data breaches to the supervisory authority generally within 72 hours. Learn more →

Retrieval-augmented generation (RAG)

A method in which an AI first searches matching passages in your own documents for a question and forms its answer from them. Learn more →

Role-based access control (RBAC)

Permissions are assigned to roles rather than individuals; users receive rights through their role. Learn more →

S

Shadow AI

Use of AI services without the knowledge or approval of the company, for example through personal accounts. Learn more →

Single sign-on (SSO)

A method where a single sign-in grants access to multiple applications. Learn more →

Social engineering

Manipulation of people to gain information or access. Learn more →

System hardening

Reducing a system's attack surface by removing unnecessary services and applying secure settings. Learn more →

T

Token (AI)

A small unit of text into which a language model splits inputs. Length of inputs and answers and often costs are measured in tokens.

V

VLAN

Logical separation of a network into segments, for example office, guests and devices. Learn more →

VPN

Encrypted connection securely linking devices or sites to a network over the internet. Learn more →

W

Windows Autopilot

Process by which new Windows devices are configured automatically at first start. Learn more →

Windows LAPS

Solution that assigns each device its own, rotating password for the local administrator account. Learn more →

WireGuard

Modern, lean VPN protocol that underlies mesh VPNs such as NetBird. Learn more →

Z

Zero Trust

Security approach in which no user or device is trusted merely because of its network location. Learn more →