LEARN
TO DEFEND//
Train like a SOC analyst — in your browser. 90 courses, sandboxed log hunts, packet traces, phishing triage and code audits, coached by NULL, your AI companion. Earn XP, climb the leaderboard, and walk away with certificates.
HOW IT WORKS
Bite-size lessons
Every concept comes with a plain definition, a real field note and a defender’s lens — then a knowledge check that changes every attempt.
Sandboxed ranges
Hunt brute-force in auth logs, spot DNS tunnelling in captures, flag phishing red flags, find the vulnerable line of code. All simulated, all safe.
NULL, your AI coach
Ask for an explanation, a hint that doesn’t spoil the answer, a pop quiz or a study plan. NULL teaches defence, not attacks.
XP, ranks & streaks
Ten ranks from RECRUIT to ELITE OPERATOR, daily protocols, weekly missions and 22 achievements keep you coming back.
Certificates
Finish a course and generate a PDF certificate with a unique ID for your portfolio, CV or LinkedIn.
Private by design
Works offline as a PWA. No ads, no trackers, self-hosted fonts. Export or delete your data in two clicks.
COURSE CATALOGUE
From networking and Linux to cloud, detection engineering, AI security and GDPR. Each course: 8 lessons, a field challenge and a final assessment.
Cybersecurity Fundamentals
The mental model every defender starts with: assets, threats, risk and the controls that keep them in balance.
Networking Fundamentals
How data actually moves: addressing, switching, routing and the layered models defenders use to reason about traffic.
TCP/IP
The protocol suite that runs the internet — handshakes, flags, fragmentation and what they reveal to a defender.
DNS
The internet’s phone book — resolution, record types, caching and how attackers and defenders both lean on it.
HTTP & HTTPS
The language of the web: methods, headers, status codes and how TLS turns HTTP into HTTPS.
Linux Fundamentals
The shell, the filesystem and the process model — the foundation for almost every security tool you will use.
Linux Security
Hardening, auditing and monitoring Linux hosts the way production defenders do.
Windows Security
Accounts, Active Directory, event logs and the controls that protect Windows fleets.
Operating System Security
Core OS protections — memory safety features, isolation and patching — across platforms.
Cryptography Fundamentals
Ciphers, keys and hashes from first principles — what they guarantee and what they do not.
Applied Cryptography
Using cryptography correctly in real systems — modes, randomness, key management and common pitfalls.
Authentication
Proving identity: factors, protocols and the signals that reveal account takeover.
Authorization & Access Control
Deciding who can do what — models, enforcement points and the bugs that break them.
Password Security
Passwords still guard most accounts — how they are attacked, stored and replaced.
Identity & Access Management
Running identity at organisational scale: lifecycle, federation and privileged access.
Web Security Fundamentals
The browser security model, trust boundaries and the core controls every web app needs.
OWASP Web Security
The OWASP Top 10 risk categories and how defenders detect and prevent each.
SQL Injection
How untrusted input becomes database commands — and the patterns that make it impossible.
Cross-Site Scripting
When attacker-controlled script runs in a victim’s browser — types, sinks and robust defenses.
CSRF
Cross-site request forgery: how browsers attach credentials automatically and how apps stop forged actions.
Session Security
Keeping users logged in safely: session identifiers, lifetimes and hijacking defenses.
API Security
Securing machine-to-machine interfaces: object-level authorization, rate limits and schema discipline.
Secure Coding
Habits and patterns that stop vulnerabilities from being written in the first place.
JavaScript Security
Client-side risks in modern JavaScript: dangerous APIs, supply chain and browser storage.
Cloud Security
Shared responsibility, identity-first controls and the misconfigurations behind most cloud breaches.
Container Security
Images, runtimes and orchestration — securing containers from build to run.
DevSecOps
Security built into delivery pipelines — automated, fast and owned by the teams who ship.
Network Security
Segmentation, detection and secure design for the networks everything else runs on.
Firewalls
Filtering traffic with intent: rule design, statefulness and next-generation capabilities.
VPN & Secure Communications
Tunnels, protocols and the trade-offs of encrypting traffic between people and sites.
Security Monitoring
Seeing what is happening: telemetry sources, detections and the analyst mindset.
SIEM Fundamentals
Collecting, normalising and correlating logs at scale to find the signal in the noise.
Log Analysis
Reading logs like an investigator — timelines, patterns and the quiet anomalies that matter.
Incident Response
A structured response to security incidents: prepare, detect, contain, eradicate, recover and learn.
Digital Forensics
Preserving and analysing digital evidence so findings hold up to scrutiny.
Malware Analysis Fundamentals
Safely understanding malicious software through static and dynamic analysis in isolated labs.
Threat Intelligence
Turning information about adversaries into decisions defenders can act on.
Social Engineering Awareness
The human attack surface: phishing, pretexting and building a culture that reports.
Security Architecture
Designing systems that are secure by structure — zones, trust, resilience and threat modelling.
Zero Trust
Never trust, always verify — identity, device and context-driven access for every request.
Security Operations
Running a SOC: triage, escalation, metrics and automation that keep defenders effective.
Penetration Testing Fundamentals
How authorised testing works: scope, rules of engagement, methodology and reporting.
Vulnerability Assessment
Finding, scoring and prioritising weaknesses before attackers do.
Security Testing
Testing strategies that verify security requirements throughout development.
Mobile Security
Protecting apps and data on phones: platform security, storage and communication.
IoT Security
Securing connected devices with limited resources, long lifetimes and physical exposure.
Privacy & Data Protection
Handling personal data lawfully and respectfully — principles, rights and practical controls.
Secure Software Development
A security-aware lifecycle: requirements, design, build, test, release and maintain.
Capture The Flag Fundamentals
Competitive, sandboxed puzzle-solving that sharpens real defensive and analytical skills.
Cybersecurity Career Lab
Roles, skills, portfolios and learning paths for building a career in security.
Wireless Security
Securing Wi-Fi from the radio layer up: protocols, authentication modes and the rogue access points that threaten them.
Email Security: SPF, DKIM & DMARC
Authenticating mail, stopping spoofing and hardening the channel that delivers most attacks.
Ransomware Defense
How modern ransomware operations unfold and the layered controls that stop or survive them.
Active Directory Defense
Protecting the directory at the heart of most enterprises: tiering, credential hygiene and attack-path reduction.
Kubernetes Security
Securing clusters end to end: API access, workloads, supply chain and runtime.
AWS Security Essentials
Identity, logging, network and data protection on Amazon Web Services.
Microsoft Entra & Azure Security
Identity-first security in the Microsoft cloud: conditional access, privileged roles and logging.
Software Supply Chain Security
Protecting everything that goes into your software: dependencies, builds, artifacts and signing.
GraphQL Security
Securing flexible query APIs: authorization per field, query cost and schema exposure.
OAuth & OpenID Connect Deep Dive
Delegated authorization done right: flows, tokens, PKCE and the misconfigurations that break them.
PKI & Certificate Management
Running public key infrastructure: issuance, lifecycle, revocation and automation.
Post-Quantum Cryptography
Preparing for quantum-capable adversaries: new algorithms, migration planning and crypto-agility.
Detection Engineering
Building, testing and maintaining detections as code that catch real attacker behaviour.
Threat Hunting
Proactively searching for adversaries that slipped past automated defenses.
Memory Forensics
Capturing and analysing volatile memory to find evidence that never touches disk.
Cloud Incident Response
Responding to incidents where the evidence lives in APIs, logs and ephemeral resources.
ICS / OT Security
Protecting industrial control systems where availability and safety come first.
AI & LLM Security
Building and defending applications that use large language models.
Bug Bounty & Responsible Disclosure
Finding and reporting vulnerabilities ethically, within the rules of public programs.
Purple Teaming
Red and blue working together to measure and improve detection and response.
Secrets Management
Storing, distributing and rotating credentials so they never leak into code or logs.
Backup & Disaster Recovery
Designing recovery that actually works when systems fail or are attacked.
Endpoint Hardening
Reducing what an attacker can do on laptops, desktops and servers.
macOS Security
Built-in Apple protections, management and monitoring for Mac fleets.
Risk Management & Frameworks
Turning security into managed business risk with recognised frameworks.
GDPR for Engineers
Practical data protection for people who build systems that handle personal data.
ISO 27001 & SOC 2 Essentials
How certification and attestation frameworks work and what auditors actually look for.
Security Awareness Programs
Designing awareness that changes behaviour rather than ticking a compliance box.
OSINT for Defenders
Using open-source intelligence ethically to understand and reduce your organisation’s exposure.
DDoS Resilience
Keeping services online under volumetric, protocol and application-layer floods.
Protective DNS & DNS Defense
Using DNS as a security control and protecting your own domains.
Browser Security
How browsers isolate sites and the features developers use to harden web apps.
Threat Modeling Workshop
Running practical threat modelling sessions that produce real design changes.
Reverse Engineering Fundamentals
Understanding compiled software safely to analyse malware and verify behaviour.
Vulnerability Management Program
Running vulnerability management as a continuous, risk-based business process.
SOC Analyst Bootcamp
A practical first-year toolkit for triaging, investigating and escalating alerts.
Network Traffic Analysis
Reading flows and packets to spot exfiltration, command and control and lateral movement.
Secure Authentication Design
Designing sign-in, recovery and session flows that resist real-world attacks.
Privacy Engineering
Building privacy into systems with concrete technical patterns.
Security Leadership & Strategy
Leading security programs: strategy, communication, budgets and people.
PRICING
Everything you need to start.
- 50 courses · 501 levels
- All 8 training ranges + daily protocols
- XP, ranks, streaks, 22 achievements
- PDF certificates
- NULL AI · 15 online questions / day
- Optional free account & leaderboard
Pay once. Keep it.
- 40 advanced PRO modules (+400 levels)
- Cloud, Kubernetes, detection engineering, threat hunting, memory forensics, AI security, GDPR & more
- NULL AI · 150 online questions / day
- Every future PRO module, free
- PRO badge on the leaderboard
- Supports an independent developer
Checkout by Gumroad. You’ll receive a license key — paste it in the app under Account. One license per operator account.
LEADERBOARD
The board is empty — the first operators to opt in take the top spots. Claim yours →
FAQ
Is NULL//SEC really free?
50 courses, all eight training ranges, daily protocols, achievements, certificates and the AI companion are free. PRO is an optional one-time purchase that unlocks 40 advanced modules, more daily AI questions and cloud backup.
Is PRO a subscription?
No. PRO is a single payment of €39 through Gumroad. You get a license key, paste it into the app once, and the 40 PRO modules stay unlocked on your account.
Do I need an account?
No. You can train without one — progress is saved in your browser. A free account adds cross-device sync, the public leaderboard (opt-in) and online AI answers.
Are the challenges legal?
Yes. Every challenge is a sandboxed simulation with fabricated logs, packet captures, code and inboxes. Nothing connects to or attacks real systems, and NULL is built to teach defence.
What happens to my data?
We store only what the service needs: email, callsign, a password hash and your training stats. No ads, no trackers, no analytics. You can export or delete everything yourself from the app at any time.
Are the certificates accredited?
Certificates document that you completed a NULL//SEC course and are great for portfolios and LinkedIn. They are not issued by an accredited certification body.
READY, OPERATOR?
Your first protocol is Cybersecurity Fundamentals. It takes ten minutes.