About the course


title: Secure development in .net/C#
audience: senior/medior developers, lead devs, testers and security champions (mostly comprehensible for juniors as well)
duration: 2 days (12 hrs education time) in the standard case; 3 days if combined with additional modules (see the Related courses below)
.net specific parts are developed by: Riccardo ten Cate
Many parts developed by: Glenn ten Cate, Péter Nyilasy, Marek Zachara
With the Secure development in .net/C# course we deliver a complete set of knowledge and practicing. We can on the fly flex the course to meet the level and the experiences of the audience.


We assume that the developers attending the C# secdev course:
  • are familiar with the C# language and with the .NET framework
  • understand the HTTP protocol, HTML and Javascript
  • are familiar with basic security features of an enterprise application (authentication, authorization, the concept of a session)
  • have .net core 2.0 SDK and a suitable IDE installed on their laptop (labs desktop)


A. Intro to principles and practice of secdev

Introduction to vulnerabilities

  • 'Into the middle of things' hands-on hacking
  • Playing with untuned source code scanning
  • Playing with identifying real threats and security requirements

Intro to secure coding

  • OWASP ASVS topics, an introduction to the areas to protect
  • How a properly designed infrastructure architecture should be built

Intro to practical secure development

  • Setting up the right security requirements
  • Create and train security champions
  • S-SDLC basics, secure development as integral part of SDLC
  • Automatic tools and their values, non-automatic tools, pentests, peer code review, assisted code-review

B. Code security

Common server-side vulnerabilities and their defense

  • Injections: SQLi, XML injections, JSON, XPath, XSS, cookie injection, open redirection, http header injection
    Path traversal, XXE, Buffer overflow, Zip bomb, Million laugh, RFI, Insecure file upload, Code execution
  • Insecure direct object reference

Common client-side vulnerabilities and their defense

  • XSS (types, impact, causes, defenses, other html injections, BeEF)
  • CSRF, Clickjacking, Same-origin policy, CORS
  • Tabnabbing

Server-side defense

  • Input validation vs encoding

Some security features

  • Security logging, exception handling

C. Security design

Security by design

  • Threat modelling
  • Separation of duties, trust boundaries, security boundaries, defence in depth, principle of least privilege, minimising the attack surface, risk driven mitigation
  • Business logic vulnerabilities


  • Cryptography basics
  • TLS, ciphersuites
  • HTTP certificate pinning
  • Perfect forward secrecy, certificate transparency

Http configuration

  • CSP, HSTS, Cookie settings, x-content-type-options

Access management

  • Authentication principles, session management, authorization
  • RESTful authorization (OAuth2, OpenID Connect)
  • JSON web tokens, JWT

Server-side defense

  • API security, design and implementation
  • Web service security [optional]
  • Attack surface

Other security features

  • Audit support (separate audit logs, managing debug logs)
  • Intrusion detection, correct reactions
  • Protecting the admin interface

D. Framework/language specifics

Secure coding in .net/C#

Developed by Riccardo ten Cate
  • Security features of .NET and what kind of protection they serve
  • C# language security (is C# a secure language?)
  • .NET-specific issues
    • Numeric overflow, automatic conversions
    • Serialization
    • Authentication, membership, provider model
    • Login controls, session management
    • Role based authorization
    • ViewState
    • Identity server
    • OAuth
  • Cryptography in .NET
    • How to use a key vault
    • How to test entropy of secure random solutions

JS frameworks [optional]

  • Angular
  • React

HTML5 [optional]

  • Local storage/session storage
  • Web messaging, web sockets

E. Security testing and audit [optional]

Practicing is part of many of the above blocks. We start off basic hacking challenges, but the real exercises are about fixing vulnerable codes, and tasks when attendees need to assess code and an application on their own. We mostly offer cloud based facilities to run the exercise environments, so no local installation is needed.

Hands-ons with vulnerable apps

  • For most of the courses there are intentionally vulnerable applications which we use to demonstrate and learn specific vulnerabilities and how to fix them.
  • In some cases we use public "damn vulnerable" applications, in some cases we prepared our own applications to practice with.

DIY sonarqube code checking

  • We assume that developers should be capable of running basic automated tests against the security of their codes on their own. And also be able to tune the SCA tools to produce reasonable false positive and valuable findings ratio.
  • Normally we teach how to use security plugins of Sonarqube.
  • We provide sample codes to test. Though the best experience is achieved when developers run the security SCA against their own codes.
  • See also the extra, on-demand block of 'Assisted code-review lab' below for practicing on your own codes.

DIY ASVS self-audit

  • OWASP ASVS is the current standard for assessing the security quality and design flaws of a (web) application, and it's the developers who know the answers to the ASVS audit questions. So we take developers to a short journey in assessing the security properties of their applications.


Check out the trainers' bios in the Trainers section
Lead trainers:


This document describes a subject under discussion. The agenda of the training and the particulars of the planned delivery may change during further iterations of the discussion.