Computer Science · Intermediate
Cybersecurity
How systems actually get broken into — taught defensively, so you can protect the ones you build.
- Lessons
- 18 lessons
- Total runtime
- 50 hours of video
- Modules
- 5 modules
- Optional lessons
- 14 optional
Free. No account.
About this course
Security is not a feature you add at the end. It is a property of a whole system, and it fails at the joins — the forgotten admin page, the dependency nobody updated, the person who answered the phone. Understanding that is more valuable than memorising any particular attack.
This course is framed defensively throughout. The reason it covers how intrusions work is that you cannot defend a system whose failure modes you have never seen; every competent security practitioner understands attacks, and understanding them is what the material is for. The penetration testing course in the last module is the standard introductory treatment of that ground.
One thing to be unambiguous about: the techniques here are for systems you own or have written permission to test. That is not a formality. Scanning or probing machines you have no authorisation for is a criminal offence in most countries regardless of intent, and "I was learning" has never been a defence. Set up your own lab — deliberately vulnerable virtual machines exist precisely for this — and stay in it.
About five hours on the required path, and around fifty in total once the optional lessons are included — Harvard's CS50 security course, a cryptography module, network defence, and twelve hours of hands-on ethical hacking. The threat-modelling habit is the part that outlasts any specific tool: ask what you are protecting, from whom, and what happens when a given control fails.
What you'll be able to do
- Explain why security is a property of a system rather than a feature of a component
- Threat-model a small application: assets, adversaries, and failure consequences
- Describe how common attacks work — injection, weak authentication, social engineering
- Understand the networking underneath the attacks well enough to reason about defences
- Apply the basics properly: least privilege, patching, encryption in transit and at rest
Curriculum
18 lessons · 50 hours
The Mindset
5 lessons · 1h 33m
- 01CompletedCybersecurityCrashCourseVideoThreat models, authentication and the idea that security is a whole-system property. Twelve minutes, and the framing that makes the rest of the course something other than a list of attacks.12m
- 02CompletedComputer NetworksCrashCourseVideoA refresher on what is physically happening between two machines. Most attacks are attacks on a protocol, so the protocol has to be familiar first.12m
- 03CompletedThe InternetCrashCourseVideoIP, TCP and DNS as layers. DNS in particular is the target of a whole family of attacks, and it is worth knowing exactly how much trust it asks you to extend.12m
- 04CompletedHow I Would Learn Cyber Security If I Could Start OverOptionalUnixGuy | Cyber SecurityVideoOrientation on the field rather than the subject — which specialisms exist, which certifications matter, and which parts of the advice online are marketing. Useful before committing months to it.23m
- 05CompletedThe Hacker's RoadmapOptionalNetworkChuckVideoA second opinion on the same question, stronger on the networking and systems groundwork most people skip in a hurry to get to the offensive tools.34m
The Fundamentals
3 lessons · 13h 29m
- 06CompletedCyber Security Full Course for BeginnerMy CSVideoThe broad survey: terminology, categories of threat, and the defensive controls that address them. Ground-level material, and the right place to be before anything hands you a tool.4h 30m
- 07CompletedHarvard CS50's Introduction to CybersecurityOptionalfreeCodeCamp.orgVideoA full Harvard course, and the most rigorous item here. Organised around threats to systems you own rather than around tools, which is exactly the framing this subject needs.7h 44m
- 08CompletedCybersecurity for BeginnersOptionalGrow with GoogleVideoFrom Google's certificate programme, and pitched at someone considering security as a job. Lighter than CS50 and clearer about what the day-to-day work involves.1h 15m
Cryptography
4 lessons · 38m
- 09CompletedEncryption and Public KeysOptionalKhan AcademyVideoSeven minutes on the idea that makes the internet possible: two strangers agreeing on a secret in public. Start here.7m
- 10CompletedAsymmetric Encryption — Simply ExplainedOptionalSimply ExplainedVideoPublic and private keys with a clean analogy that does not fall apart under inspection, which is rarer than it should be.5m
- 11CompletedSymmetric vs Asymmetric EncryptionOptionalPractical NetworkingVideoWhy real systems use both — asymmetric to agree a key, symmetric to move the data. This is what TLS is actually doing on every page you load.14m
- 12Completed7 Cryptography Concepts Every Developer Should KnowOptionalFireshipVideoHashing, salting, signing and key exchange, at speed. The practical vocabulary rather than the mathematics — enough to stop you storing passwords badly.12m
Networks and Defence
3 lessons · 3h 26m
- 13CompletedInternet Networks and Network SecurityOptionalGrow with GoogleVideoNearly every attack crosses a network, so the network layer is where most defence happens. An hour on firewalls, segmentation and monitoring.1h 9m
- 14CompletedCybersecurity Architecture — NetworksOptionalIBM TechnologyVideoDefence in depth and zero trust explained as design decisions rather than slogans. Half an hour that changes how you lay out a system.28m
- 15CompletedAPI Security FundamentalsOptionalfreeCodeCamp.orgVideoThe most directly applicable lesson here if you build software rather than defend networks — authentication, authorisation, rate limiting and the ways APIs leak data.1h 49m
How Attacks Actually Work
3 lessons · 30h 53m
- 16CompletedFull Ethical Hacking Course - Network Penetration Testing for BeginnersOptionalfreeCodeCamp.orgVideoOptional, and long. The standard introduction to offensive technique, included because defending a system requires knowing how it is probed. Run everything against your own lab machines only — unauthorised scanning is a crime in most jurisdictions, whatever the motive.15h
- 17CompletedHands-On Cybersecurity and Ethical HackingOptionalfreeCodeCamp.orgVideoThree and a half hours of practical work in a lab environment. Shorter than the penetration testing course above and a reasonable substitute for it.3h 36m
- 18CompletedEthical Hacking in 12 HoursOptionalThe Cyber MentorsVideoThe most complete free offensive-security course there is, from a practitioner who trains professionally. Do this only against machines you own or deliberately vulnerable practice targets.12h 17m
Credits
Every lesson in this course was made by one of these channels. Tubeversity sequenced them; it did not make them. If a course is useful to you, the people below are the ones who earned it.