Desktop application security in Python

3 days
On-site or online

21 Labs


8 Case Studies




Python developers working on desktop applications


General Python development

Standards and references

CWE and Fortify Taxonomy

Group size

12 participants


  • Cyber security basics
  • Input validation
  • Security features
  • Using vulnerable components
  • Cryptography for developers
  • Common software security weaknesses
  • Wrap up

What you will learn

  • Getting familiar with essential cyber security concepts
  • Input validation approaches and principles
  • Identify vulnerabilities and their consequences
  • Learn the security best practices in Python
  • Correctly implementing various security features
  • Managing vulnerabilities in third party components
  • Understanding how cryptography supports security
  • Learning how to use cryptographic APIs correctly in Python


Your application written in Python works as intended, so you are done, right? But did you consider feeding in incorrect values? 16Gbs of data? A null? An apostrophe? Negative numbers, or specifically -1 or -2^31? Because that’s what the bad guys will do – and the list is far from complete.

Handling security needs a healthy level of paranoia, and this is what this course provides: a strong emotional engagement by lots of hands-on labs and stories from real life, all to substantially improve code hygiene. Mistakes, consequences, and best practices are our blood, sweat and tears.

All this is put in the context of Python, and extended by core programming issues, discussing security pitfalls of the programming language.

So that you are prepared for the forces of the dark side.

So that nothing unexpected happens.


Table of contents

  • Cyber security basics
  • Input validation
    • Input validation principles
    • Denylists and allowlists
    • What to validate – the attack surface
    • Where to validate – defense in depth
    • When to validate – validation vs transformations
    • Validation with regex
    • Regular expression denial of service (ReDoS)
    • Lab – ReDoS
    • Dealing with ReDoS
    • 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
          • Parameterized queries
          • Lab – Using prepared statements
          • Database defense in depth
          • Case study – Hacking Fortnite accounts
      • Code injection
        • Code injection via input()
        • OS command injection
          • Lab – Command injection
          • OS command injection best practices
          • Avoiding command injection with the right APIs
          • Lab – Command injection best practices
          • Case study – Shellshock
          • Lab – Shellshock
          • Python module hijacking
  • Input validation
    • Integer handling problems
      • Representing signed numbers
      • Integer visualization
      • Integers in Python
      • Integer overflow
      • Integer overflows in ctypes and numpy
      • Lab – Integer problems in Python
    • Files and streams
      • Path traversal
      • Lab – Path traversal
      • Path traversal best practices
      • Lab – Path canonicalization
  • Security features
    • Authentication
      • Authentication basics
      • Multi-factor authentication (MFA)
      • Time-based One Time Passwords (TOTP)
      • Case study – PayPal 2FA bypass
      • Password management
        • Inbound password management
        • Outbound password management
          • Hard coded passwords
          • Best practices
          • Lab – Hardcoded password
          • Protecting sensitive information in memory
            • Challenges in protecting memory
    • Information exposure
      • Exposure through extracted data and aggregation
      • Case study – Strava data exposure
    • Platform security
      • Python platform security
        • The Python ecosystem and its attack surface
        • Python bytecode and security
        • Security features offered by Python
        • PEP 578 and audit hooks
        • The difficulties of sandboxing untrusted code
        • Sandboxing Python
  • Using vulnerable components
  • Cryptography for developers
    • Cryptography basics
    • Cryptography in Python
    • Elementary algorithms
      • Random number generation
        • Pseudo random number generators (PRNGs)
        • Cryptographically secure PRNGs
        • Using virtual random streams
        • Weak PRNGs
        • Using random numbers
        • Lab – Using random numbers in Python
        • Case study – Equifax credit account freeze
      • Hashing
        • Hashing basics
        • Common hashing mistakes
        • Hashing in Python
        • Lab – Hashing in Python
    • Confidentiality protection
      • Symmetric encryption
        • Block ciphers
        • Modes of operation
        • Modes of operation and IV – best practices
        • Symmetric encryption in Python
        • Lab – Symmetric encryption in Python
      • Asymmetric encryption
        • The RSA algorithm
          • Using RSA – best practices
          • RSA in Python
      • Combining symmetric and asymmetric algorithms
      • Key exchange and agreement
        • Key exchange
        • Diffie-Hellman key agreement algorithm
        • Key exchange pitfalls and best practices
    • Integrity protection
      • Authenticity and non-repudiation
      • Message Authentication Code (MAC)
        • Calculating HMAC in Python
        • Lab – Calculating MAC in Python
      • Digital signature
        • Digital signature with RSA
        • Elliptic Curve Cryptography
          • ECC basics
          • Digital signature with ECC
        • Digital signature in Python
          • Lab – Digital signature with ECDSA in Python
    • Public Key Infrastructure (PKI)
      • Some further key management challenges
      • Certificates
        • Certificates and PKI
        • X.509 certificates
        • Chain of trust
        • PKI actors and procedures
        • Certificate revocation
  • Common software security weaknesses
    • Time and state
      • Race conditions
        • File race condition
          • Time of check to time of usage – TOCTTOU
          • TOCTTOU attacks in practice
          • Lab – TOCTTOU
          • Insecure temporary file
    • Errors
      • Error and exception handling principles
      • Exception handling
        • In the except block. And now what?
        • Empty except block
        • Lab – Exception handling mess
  • Wrap up
    • Secure coding principles
      • Principles of robust programming by Matt Bishop
      • Secure design principles of Saltzer and Schroeder
    • And now what?
      • Software security sources and further reading
      • Python resources


3 days Session Price

2250 EUR / person

  • Live, instructor led classroom training
  • Discussion and insight into the hacker’s mindset
  • Hands-on practice using case studies based on high-profile hacks and live lab exercises
Customized course

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