Security Fundamentals

Many believe a server without sensitive data is safe, but attackers often want processing power and IP reputation to launch botnets or phishing campaigns.

Cybercrime has evolved from lone hackers into professional criminal organisations. Learn why updating your threat model is vital for modern digital security.

Many small business owners believe they are too insignificant for cyber attacks, but automated bots and supply chain risks make every single device a target.

Many people believe that Apple computers are immune to viruses, but this is a myth. Learn why macOS security needs more than just built-in protections today.

Forcing users to change passwords every ninety days creates predictable patterns. Discover why NIST and NCSC now recommend against periodic password rotation.

Does private browsing hide your activity? Learn why incognito mode only clears local history and does not stop ISPs or websites from tracking your identity.

A security baseline is a documented minimum set of controls a system must meet. Learn why baselines beat ad-hoc hardening and how CIS Benchmarks help.

Security through obscurity relies on secrecy of design as the defense. Learn why it fails as a sole control, and the nuanced role secrecy still plays in depth.

Fail-safe defaults mean a system denies by default and stays secure when something breaks. Learn the principle, fail-closed vs fail-open, and how to apply it.

Input validation checks that data matches what a program expects before using it. Learn allowlist vs blocklist, why it is not a cure-all, and where it belongs.

A sandbox is an isolated environment where untrusted code can run without harming the host. Learn how they contain risk, where they are used, and their limits.

A penetration test is an authorized simulated attack that finds exploitable weaknesses before attackers do. Learn the phases, types, and why scope is sacred.

A security audit is a structured review of controls against a standard. Learn how they differ from pentests, what they cover, and why evidence matters.

Red teams attack, blue teams defend, and purple teams make them work together. Learn what each does, how they differ from a pentest, and why collaboration wins.

OSINT is intelligence gathered from publicly available sources. Learn what it covers, how attackers and defenders use it, and why your footprint is a target.

A bug bounty program pays researchers to find and report vulnerabilities legally. Learn how programs work, what scope means, and where to start.

Responsible disclosure means reporting a vulnerability privately and giving the vendor time to fix it before details go public. Here is how it works.

A CVE is a unique public identifier for a specific security vulnerability. Learn what CVE IDs mean, who assigns them, and how they drive patching.

A botnet is a network of compromised devices controlled remotely by an attacker. Learn how botnets are built, what they do, and how they are taken down.

Ransomware encrypts a victim’s data and demands payment to release it. Learn how modern attacks work, why backups matter, and what double extortion means.

Malware is a family, not one thing. Learn the working taxonomy — virus, worm, trojan, ransomware, spyware, rootkit — and what actually sets each type apart.

Social engineering attacks the human, not the machine, using trust and urgency to bypass technical controls. Learn its main techniques and real defenses.

Multi-factor authentication requires two or more independent proofs of identity. Learn the three factors, why SMS is weakest, and what phishing-resistant means.

A salt is random data added to each password before hashing. Learn how salts defeat rainbow tables, why every password needs a unique one, and pepper.

Encoding, encryption, and hashing are constantly confused, yet only one provides security. Learn what each does, when to use it, and why encoding is not one.

Hashing is a one-way fingerprint; encryption is reversible with a key. Confusing them causes real security bugs. Learn the difference and when to use each.

Symmetric encryption uses one shared key; asymmetric uses a public/private key pair. Learn how each works, their trade-offs, and why real systems use both.

Vulnerability, exploit, and payload are three different things people call "a hack." Learn what each is, how they chain, and why the distinction matters.

Security risk is the chance a threat exploits a vulnerability and the harm if it does. Learn the risk equation, how to rank risks, and four ways to treat them.

Authentication proves who you are; authorization decides what you may do. Learn the difference, why apps confuse them, and how each one fails in practice.

Least privilege means giving every user, process, and service only the access it needs and no more. Learn why it limits blast radius and how to apply it.

An attack surface is every point where an attacker can try to enter or extract data from a system. Learn how to map yours and shrink it deliberately.

Defense in depth means layering independent security controls so that one failure is not a breach. Learn where the idea comes from and how to apply it well.

The CIA triad names the three goals of every security control: confidentiality, integrity, and availability. Learn what each means and how they trade off.

Threat modeling is a structured way to find what can go wrong before it does. Learn its four core questions, the STRIDE framework, and how to run one.

Many organisations wrongly assume that moving to the cloud removes all security risks, but the shared responsibility model means users must still protect data.

Does encryption protect all your privacy? Learn how metadata and key management can expose sensitive information even when content remains scrambled.

Cyber insurance provides financial support after a data breach, but it cannot recover lost trust or stop an attack. Learn why security controls are essential.

An air gap prevents network attacks, but malware can still enter via USB sticks or laptops. Learn why isolation is a layer of defence, not a total solution.

A security certification provides a minimum baseline of discipline but cannot guarantee total protection against modern threats and sophisticated cyber attacks.

Learn why security through obscurity is a myth and how reverse engineering allows attackers to find flaws in closed source software despite the secrecy.

Discover why deleting a file and emptying the bin does not remove sensitive information from a hard drive and how data recovery tools find hidden files.

A nonce is a number used once to stop replay attacks and guarantee freshness. Learn how nonces work in crypto, CSP, and auth, and why reuse is dangerous.

Entropy is the unpredictability that keys, tokens, and passwords depend on. Learn why weak randomness breaks cryptography, and PRNGs versus CSPRNGs.

Encryption is only as strong as how you handle the keys. Learn the key lifecycle, why key storage is the hard part, and what HSMs and rotation are for.

Threat intelligence is evidence-based knowledge about adversaries that informs decisions. Learn its three levels, and how to make it actually useful.

An indicator of compromise is forensic evidence that a breach may have occurred. Learn the common IOC types, how they are used, and why IOCs alone fall short.

Non-repudiation means an actor cannot credibly deny an action they took. Learn how digital signatures and logging provide it, and why it extends the CIA triad.

A race condition is a bug where the timing of events changes the outcome — and attackers can exploit it. Learn the TOCTOU pattern and how to prevent them.

Fuzzing throws malformed and random input at software to find crashes and bugs. Learn how fuzzers work, why they find flaws humans miss, and where it is used.

CVSS turns a vulnerability’s traits into a 0–10 severity score. Learn what the metrics mean, what the number does and does not tell you, and how to use it well.

A backdoor is a hidden way to bypass normal authentication and regain access to a system. Learn the types, how attackers plant them, and why they are dangerous.

Lateral movement is how attackers spread from their first foothold to their real target. Learn the techniques, why it is a detection point, and how to slow it.

Privilege escalation is how an attacker turns limited access into greater control. Learn the two types, common causes, and how to shut it down.

A rootkit is malware built to hide — concealing its presence while keeping privileged access. Learn how they work, why they resist detection, and how to defend.

A certificate authority issues the digital certificates that vouch for identities online. Learn what CAs do, how they validate, and why they are load-bearing.

PKI is the system of keys, certificates, and authorities that binds public keys to real identities. Learn what problem it solves and how the trust chain works.

A digital signature proves who created a message and that it was not altered. Learn how signatures use hashing and private keys, and what they really prove.

Zero trust drops the trusted internal network for one rule: never trust, always verify. Learn the core principles, what it is not, and how teams adopt it.

MITRE ATT&CK is a free, curated knowledge base of real attacker tactics and techniques. Learn how it is structured and how defenders use it to measure coverage.

The Cyber Kill Chain models an intrusion as seven stages, from reconnaissance to actions on objectives. Learn how defenders use them to disrupt attacks.

Perfect forward secrecy ensures that stealing a server’s long-term key cannot decrypt past traffic. Learn how ephemeral keys make it work and why TLS needs it.

A buffer overflow writes more data than a buffer can hold, corrupting memory and enabling code execution. Learn how the classic attack works and its defenses.