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Reference
Free, practical cybersecurity cheat sheets — the commands, flags and checklists worth coming back to, each with a visible last-verified date and none of it behind an email form or a PDF wall.
New here? The Cyber Kill Chain maps every sheet below onto a stage of a real attack — a good place to start.
The offensive chain runs end to end: map a target with the OSINT & recon sheet, scan it with Nmap, make sense of what's open via common ports, catch a shell with the reverse shell sheet, then climb with Linux privilege escalation.
The AI-security set covers what everyone's asking about: the OWASP LLM Top 10, prompt injection, jailbreak techniques, AI agent security and RAG security — with a hands-on LLM security lab to practise on.
On the blue-team side, watch the wire with tcpdump, read Linux logs with journalctl, search them at scale with SPL, and triage a suspicious file safely with malware analysis sandboxes. Everything is written to be scanned in seconds and trusted — spot something out of date? Tell me.
Install Software Safely: Sources, Hashes, Signatures and Licenses (Tech+)
ExplainerPartly testedLevel beginnerTime ~25 minTool PowerShell, winget, aptCost freeExam Tech+ 3 What you’ll know Where safe software comes from, how to prove a download is the…
Programming Languages Compared: Compiled, Interpreted, Markup and Query (Tech+)
ExplainerPartly testedLevel beginnerTime ~25 minTool Python, gcc, Bash, PowerShell, SQLiteCost freeExam Tech+ 4 What you’ll know The difference between compiled, interpreted, scripting, markup and query languages;…
Lock Down Your Own Devices: Updates, MFA, Encryption and Backups (Tech+)
ExplainerPartly testedLevel beginnerTime ~20 minTool Windows Settings, PowerShellCost freeExam Tech+ 6 What you’ll know The eight habits that protect a computer or phone: updates, antivirus, a…
NTP and Time Sync Explained: Stratum, Offset and Why Logs Need the Right Time (Network+)
ExplainerLevel beginnerTime ~10 minTool timedatectl, w32tmCost freeExam N+ 3 · also 5 What you’ll know How the Network Time Protocol keeps clocks in step, what stratum,…
Spanning Tree (STP) Explained: Build a Switch Loop and Watch STP Fix It (Network+)
ExplainerLevel beginnerTime ~15 minTool ip, bridge (Linux)Cost freeExam N+ 2 · also 5 What you’ll know Why two cables between switches can take a network down,…
The OSI Model Explained: One Web Request Through All 7 Layers (Network+)
ExplainerLevel beginnerTime ~20 minTool ip, curl, tcpdumpCost freeExam N+ 1 · also 5 What you’ll know The seven OSI layers, what each one does, which devices…
Incident Response Explained: The Six Steps and Evidence Basics (Security+)
ExplainerLevel beginnerTime ~15 minTool PowerShell, bashCost freeExam Sec+ 4 What you’ll know The six phases of incident response in order, what happens in each, how to…
Email Security Explained: SPF, DKIM and DMARC (Security+)
ExplainerLevel beginnerTime ~12 minTool dig, PowerShellCost freeExam Sec+ 4 · also 2 What you’ll know Why anyone can type any “From” address, how SPF, DKIM and…
Risk Management Explained: SLE, ALE, RTO and the Four Responses (Security+)
ExplainerLevel beginnerTime ~15 minTool PythonCost freeExam Sec+ 5 · also 4 What you’ll know How to put a dollar figure on a risk, the four ways…
Cryptography and PKI Explained: Hashing, Encryption and Certificates (Security+)
ExplainerLevel beginnerTime ~20 minTool OpenSSL, PowerShellCost freeExam Sec+ 1 · also 3, 4 What you’ll know The difference between hashing and encryption, symmetric vs asymmetric keys,…
Data and Databases Explained: Tables, SQL and Backups (Tech+)
ExplainerLevel beginnerTime ~15 minTool Python, SQLiteCost freeExam Tech+ 5 What you’ll know Why data is worth protecting, structured vs unstructured data, how a database table works…
Programming Basics Explained: Variables, Loops and Functions (Tech+)
ExplainerLevel beginnerTime ~15 minTool Python, PowerShellCost freeExam Tech+ 4 What you’ll know What variables, data types, branches, loops, functions and objects are; the difference between compiled,…
Operating Systems, Software and File Systems Explained (Tech+)
ExplainerLevel beginnerTime ~12 minTool PowerShell, bashCost freeExam Tech+ 3 What you’ll know What the operating system does for you, how the main ones differ, why a…
Computer Hardware Explained: CPU, RAM, Storage and Ports (Tech+)
ExplainerLevel beginnerTime ~15 minTool PowerShell, bashCost freeExam Tech+ 2 What you’ll know What each main part of a computer does, how to tell a fast drive…
Binary, Hex and Data Sizes Explained (Tech+)
ExplainerLevel beginnerTime ~12 minTool PowerShell, bashCost freeExam Tech+ 1 What you’ll know What a bit and a byte are, how to read binary and hex, why…
Network Security Explained for Network+: Attacks, AAA and Hardening
ExplainerTime ~20 minCost freeExam N+ 4 What you’ll know The ideas behind Network+ Domain 4: the CIA triad, AAA and 802.1X, the attacks the exam names…
High Availability, Disaster Recovery and Network Documentation (Network+)
ExplainerTime ~15 minCost freeExam N+ 3 What you’ll know How to measure availability and recovery, how networks avoid single points of failure, how to back up…
Cloud Networking and SDN Explained (Network+)
ExplainerTime ~15 minCost freeExam N+ 1 · also 2, 4 What you’ll know What the cloud service models mean, how a cloud network (a VPC) is…
Network Cabling and Connectors Explained (Network+)
ExplainerTime ~15 minTool ethtool, Get-NetAdapterCost freeExam N+ 1 · also 2, 5 What you’ll know Which copper category carries which speed and how far, when fiber…
Wi-Fi Standards, Bands and Channels Explained (Network+)
ExplainerTime ~15 minTool netsh, nmcliCost freeExam N+ 2 · also 1, 4, 5 What you’ll know Which Wi-Fi standard is which, why 2.4 GHz is crowded…
Bash Guide
Straightforward guide to bash fundamentals and scripting. Covers shell basics, variables, control flow, functions and common patterns. Useful for anyone writing infrastructure code, automation or incident…
90 Days of Cybersecurity, Hands-On: Free Labs for Every Block
CompanionBlocks 11Cost freePace your ownNot affiliated 0 / 11 steps What this is 90DaysOfCyberSecurity is one of the most popular free study plans on GitHub (about…
Bug Bounty Platforms Compared: Where to Start
ReferenceFormat platform tiersTopic bug bountyCost free to start There are a lot of bug bounty and crowdsourced-security platforms, and a list of logos tells you nothing…
Study Once, Earn Two: How Cybersecurity Certs Stack, Renew Each Other and Shorten the CISSP Clock
ReferenceCareer · certificationsLevel Beginner to intermediateWritten guide · no lab neededExam Security+ · CySA+ · PenTest+ · CISSP Most cert advice treats every exam as its…
OWASP/wstg
A structured framework for web application security testing, covering reconnaissance through post-test activities. Organized by testing category rather than vulnerability type, making it practical for both…
HackTricks-wiki/hacktricks
A sprawling wiki of tactics and techniques gathered from CTFs, penetration tests, and security research. Covers everything from basic enumeration to privilege escalation and post-exploitation across…
EvanThomasLuke/Awesome-AI-Security-Skills
Curated list of skills, tools, and resources for security work involving AI systems. Covers threat modeling, red-teaming, prompt injection, model extraction, and defensive practices. Useful for…
LOLBAS-Project/LOLBAS
A curated collection of legitimate Windows binaries and scripts that attackers abuse to evade detection and achieve their objectives. Each entry documents the binary, its abuse…
danielmiessler/SecLists
A comprehensive collection of wordlists, payloads, and patterns organized by type and use case. Covers usernames, passwords, fuzzing inputs, sensitive data signatures, web shells and more.…
GTFOBins/GTFOBins.github.io
A searchable reference of Unix binaries that can be abused to escape restricted environments or escalate privilege. Covers common tools like find, tar, and sudo with…