Security-Fundamentals

The CIA triad is a core security model that frames how systems protect secrecy, correctness, and dependable access.

Defense in depth is the practice of using multiple security layers so one control failure does not expose the whole system.

Least privilege limits users, services, and systems to the minimum access needed for their legitimate work.

Attack surface describes the set of exposed systems, interfaces, identities, and pathways an attacker could potentially target.

A threat is a potential source of harm that could exploit weaknesses or otherwise affect a system, user, or organization.

A vulnerability is a weakness in software, configuration, process, or design that could be used to compromise security.

Risk is the possibility that a threat will cause meaningful harm in a specific context, taking impact and likelihood into account.

An exploit is a method or piece of code used to take advantage of a vulnerability and cause unauthorized behavior.

Mitigation is the action taken to reduce the likelihood or impact of a security problem when risk cannot simply be ignored.

A security control is a safeguard or measure used to prevent, detect, correct, or otherwise reduce security risk.

Security misconfiguration is a condition where systems, applications, or cloud resources are set up in ways that weaken intended protections.

An attack vector is the path or method a threat uses to reach a target system, user, or workload.

Blast radius is the scope of systems, data, users, or operations that could be affected when one component is compromised or fails.

Secure by default means systems and products start in the safer configuration unless an administrator deliberately changes them.

A zero-day vulnerability is a security flaw that is newly discovered or not yet remediated, leaving defenders little or no patch window.

An attack path is the sequence of weaknesses, opportunities, or trust relationships an attacker could combine to reach a target.

Crown jewels are the systems, identities, data sets, or processes whose compromise would cause outsized harm to the organization.

Least functionality is the practice of enabling only the features, services, ports, components, and capabilities a system actually needs to perform its intended job.

Zero trust is a security model that avoids granting broad implicit trust based only on network location or prior access.

Security by design is the practice of considering security requirements and risks during planning and architecture instead of treating them as afterthoughts.

Privilege escalation is the gain of more access or authority than a user, process, or workload was originally meant to have.