Web application security in C# training

Day 1

Security basics

What is security?

Threat and risk

Types of threats against computer systems

Consequences of insecure software

Constraints and the market

Bugs, vulnerabilities and exploits

Categorization of bugs

• Seven pernicious kingdoms
• Common Weakness Enumeration (CWE)
• CWE/SANS Top 25 Most Dangerous Software Errors
• Vulnerabilities in the environment and the dependencies

The OWASP Top Ten

A1 - Injection

• Injection principles
• Injection attacks
• SQL injection
• SQL injection basics
• Lab – SQL injection
• Attack techniques
• Content-based blind SQL injection
• Time-based blind SQL injection
• SQL injection best practices
• Input validation
• Output encoding
• Parameterized queries
• Other best practices
• Lab – Using prepared statements
• Case study – Hacking Fortnite accounts
• Code injection
• Command injection
• Lab – Command injection
• Command injection best practices
• Lab – Command injection best practices
• Case study – Command injection
• Script injection
• Injection best practices
• Input validation
• Output sanitization
• Encoding and escaping the output
• Encoding challenges

A2 - Broken Authentication

• Authentication basics
• Authentication weaknesses
• Spoofing on the Web
• Case study – PayPal two factor authentication bypass
• Password management
• Inbound password management
• Storing account passwords
• Plaintext passwords at Facebook
• Lab – Why just hashing passwords is not enough?
• Dictionary attacks and brute forcing
• Salting
• Adaptive hash functions for password storage
• Password in transit
• Password policy
• Weak and strong passwords
• Using passphrases
• Lab – Applying a password policy
• The Ashley Madison data breach
• The dictionary attack
• The ultimate attack
• Exploitation of the results and the lessons learnt
• Outbound password management
• Hard coded passwords
• Lab – Hardcoded password
• Password in configuration file
• Protecting sensitive information in memory
• Challenges in protecting memory
• Storing sensitive data in memory
• Lab – Storing sensitive data in memory with SecureString
• Session management
• Session management essentials
• Why do we protect session IDs – Session hijacking
• Session ID best practices
• Insufficient session expiration
• Session fixation
• Cross-site Request Forgery (CSRF)
• Lab – Cross-site Request Forgery
• CSRF best practices
• Lab – CSRF protection with tokens
• Cookie security
• Cookie security best practices
• Cookie parameters

Day 2

The OWASP Top Ten

A3 - Sensitive Data Exposure

• Information exposure
• Exposure through extracted data and aggregation
• System information leakage
• Leaking system information
• Relying on accessibility modifiers
• Lab – Inappropriate protection by accessibility modifier
• Information exposure best practices

A4 - XML External Entities (XXE)

• DTD and the entities
• Entity expansion
• External Entity Attack (XXE)
• File inclusion with external entities
• Server-side request forgery with external entities
• Lab – External entity attack
• Case study – XXE attack against some popular services
• Preventing XXE

A5 - Broken Access Control

• Access control basics
• Missing or improper authorization
• Failure to restrict URL access
• Confused deputy
• Insecure direct object reference (IDOR)
• Lab – Insecure Direct Object Reference
• Authorization bypass through user-controlled keys
• Case study – Authorization bypass on Facebook
• File upload
• Unrestricted file upload
• Best practices
• Lab – Unrestricted file upload

A6 - Security Misconfiguration

• Configuration principles
• Server misconfiguration
• Configuration management
• NET and IIS configuration best practices
• NET configuration
• IIS configuration

A7 - Cross-site Scripting (XSS)

• Cross-site scripting basics
• Cross-site scripting types
• Persistent cross-site scripting
• Reflected cross-site scripting
• Client-side (DOM-based) cross-site scripting
• Case study – Yahoo mail stored XSS
• Lab – Reflected and stored XSS
• XSS protection best practices
• Protection principles - escaping
• Additional protection layers
• Client-side protection principles
• XSS protection APIs
• Request validation in ASP.NET
• Further XSS protection techniques
• Lab – XSS best practices

A8 - Insecure Deserialization

• Serialization and deserialization challenges
• Deserializing untrusted streams
• Deserializing best practices
• Property Oriented Programming (POP)
• POP best practices
• Lab – Creating and using a POP payload

A9 - Using Components with Known Vulnerabilities

• Using vulnerable components
• Assessing the environment
• Hardening
• Importing functionality from untrusted sources
• Case study – The British Airways data breach
• Vulnerability management
• Patch management
• Vulnerability databases and scanning tools
• Vulnerability rating – CVSS
• Lab – Finding vulnerabilities of used components
• The build process and CI / CD
• Dependency checking in Cake

A10 - Insufficient Logging & Monitoring

• Logging and monitoring principles
• Logging
• Insufficient logging
• Logging best practices
• Monitoring
• Monitoring best practices

Web application security beyond the Top Ten

• Client-side security
• Same Origin Policy
• Simple request
• Preflight request
• Bypassing the Same Origin Policy
• Cross-origin resource sharing
• Frame sandboxing
• Clickjacking
• Clickjacking protection best practices
• Lab - Clickjacking
• JavaScript hijacking

Day 3

Common software security weaknesses

Input validation

• Input validation principles
• Blacklists and whitelists
• Validation with regex
• What to validate – the attack surface
• When to validate – validation vs transformations
• Where to validate – defense in depth
• Server-side vs. client-side validation
• Integer handling
• Representing signed numbers
• Integer visualization
• Integer problems
• Integer overflow
• Lab – Integer overflow
• Signed / unsigned confusion
• Lab – Signed / unsigned confusion
• Integer truncation
• Best practices
• Upcasting
• Precondition testing
• Postcondition testing
• Using big integer libraries
• Integer handling in C#
• Lab – Checked arithmetics
• Other numeric problems
• Division by zero
• Unsafe reflection
• Reflection without validation
• Lab – Unsafe reflection
• Unsafe native code
• Native code dependence
• Lab – Unsafe native code
• Some other input validation problems

Security features

• .NET platform security
• Code Access Security
• Evidences
• Permissions
• The Stack Walk
• Lab – Code Access Security
• The transparency model
• Best practices
• Lab – Experimenting with the transparency model
• Role-based security
• Principal and identity
• Role-based permissions
• Impersonation
• Lab – Role-based security
• Protecting .NET code and applications
• Code signing

Errors

• Error and exception handling principles
• Error handling
• Returning a misleading status code
• Information exposure through error reporting
• Missing custom error pages
• Exception handling
• In the catch block. And now what?
• Empty catch block
• Best practices for catch blocks
• Overly broad throws
• Catching NULL pointer exceptions
• Exception handling in C#
• Lab – Exception handling mess

Code quality

• Data
• Arrays and ToString()
• Initialization and cleanup
• Uninitialized variable
• Class initialization cycles
• Lab – Initialization cycles
• Unreleased resource
• Object oriented programming pitfalls
• Accessibility modifiers
• Inheritance and overriding
• Implementing Equals()
• Mutability
• Readonly collections
• Lab – Mutable object
• Cloning
• Cloning sensitive classes – object hijacking
• Object hijacking – best practices
• Serialization
• Serializing sensitive data
• Serialization best practices
• Lab – Serializing sensitive data
• DoS with deserialization
• Memory leaks during serialization

Wrap up

Secure coding principles

• Principles of robust programming by Matt Bishop
• Secure design principles of Saltzer and Schröder
• Some more principles

And now what?

• Further sources and readings
• .NET and C# resources

Further labs and challenges to do