DEV522: Defending Web Applications Security Essentials

Provided by SANS
GWEB Certification
Qualification level
GWEB Certification
Study type
Distance learning
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About the course

This is the course to take if you have to defend web applications!

The quantity and importance of data entrusted to web applications is growing, and defenders need to learn how to secure them. Traditional network defenses, such as firewalls, fail to secure web applications. DEV522 covers the OWASP Top 10 Risks and will help you better understand web application vulnerabilities, thus enabling you to properly defend your organization's web assets.

Mitigation strategies from an infrastructure, architecture, and coding perspective will be discussed alongside real-world applications that have been proven to work. The testing aspect of vulnerabilities will also be covered so that you can ensure your application is tested for the vulnerabilities discussed in class.

To maximize the benefit for a wider range of audiences, the discussions in this course will be programming language agnostic. Focus will be maintained on security strategies rather than coding-level implementation.

DEV522: Defending Web Applications Security Essentials is intended for anyone tasked with implementing, managing, or protecting Web applications. It is particularly well suited to application security analysts, developers, application architects, pen testers, auditors who are interested in recommending proper mitigations for web security issues, and infrastructure security professionals who have an interest in better defending their web applications.

The course will also cover additional issues the authors have found to be important in their day-to-day web application development practices. The topics that will be covered include:

  • Infrastructure security
  • Server configuration
  • Authentication mechanisms
  • Application language configuration
  • Application coding errors like SQL injection and cross-site scripting
  • Cross-site request forging
  • Authentication bypass
  • Web services and related flaws
  • Web 2.0 and its use of web services
  • XPATH and XQUERY languages and injection
  • Business logic flaws
  • Protective HTTP headers

The course will make heavy use of hands-on exercises and concludes with a large defensive exercise that reinforces the lessons learned throughout the week.


Course Syllabus

DEV522.1: Web Basics and Authentication Security


We begin day one with an overview of recent web application attack and security trends, then follow up by examining the essential technologies that are at play in web applications. You cannot win the battle if you do not understand what you are trying to defend. We arm you with the right information so you can understand how web applications work and the security concepts related to them.

We discuss the authentication aspect of web applications in depth. The vulnerability of authentication is covered, followed by examples of exploitation and the mitigations that can be implemented in the short and long term. We complete the discussion by providing information on how to discover and test for vulnerabilities.

Authorization is the last topic of discussion for the day: the goal is to make sure that applications properly control access to the appropriate resources. You will learn the right way to plan for access during the development life cycle and the common pitfalls with access control. Similar to the discussion on authentication, we start with the vulnerabilities and then move on to mitigations and testing, followed by a section on best practices on authorization.

CPE/CMU Credits: 6


  • HTTP basics
  • Overview of web technologies
  • Web application architecture
  • Recent attack trends
  • Authentication vulnerabilities and defense
  • Authorization vulnerabilities and defense


DEV522.2: Web Application Common Vulnerabilities and Mitigations


Since the Internet does not guarantee the secrecy of information being transferred, encryption is commonly used to protect the integrity and secrecy of information on the web. This course day covers the security of data in transit or on disk and how encryption can help with securing that information in the context of web application security.

We continue with a discussion about session management in web applications. We will go over a hacker's technique in attacking the session mechanism and related defense strategies. Best practices of session security will be discussed to ensure your application's session management is as strong as possible. Advanced session topics like cross-site request forgery will also be covered.

Next we will cover business logic flaws and concurrency. These are difficult topics to detect with automated scanners, so it is essential that security professionals understand these problems and avoid them at all costs.

The day ends with analysis of some basic input-related flaws, as well as SQL injection. The basic mechanics of these vulnerabilities are covered, followed by real-world attack trends. Most importantly, we delve into the mitigation of these vulnerabilities and best practices to avoid these critical vulnerabilities.

CPE/CMU Credits: 6


  • SSL vulnerabilities and testing
  • Proper encryption use in web application
  • Session vulnerabilities and testing
  • Cross-site request forgery
  • Business logic flaws
  • Concurrency
  • Input-related flaws and related defenses
  • SQL injection vulnerabilities, testing, and defense


DEV522.3: Proactive Defense and Operation Security


Day three begins with a detailed discussion on cross-site scripting and related mitigation and testing strategies, as well as HTTP response splitting.

The code in an application may be totally locked down, but if the server setting is insecure, the server running the application can be easily compromised. Locking down the web environment is essential, so we cover this basic concept of defending the platform and host.

To enable any detection of intrusion, logging and error handling must be done correctly. We will discuss the correct approach to handling incidents and logs, then dive even further to cover the intrusion detection aspect of web application security.

In the afternoon we turn our focus to the proactive defense mechanism so that we are ahead of the bad guys in the game of hack and defend. We will cover such topics such as file upload handling, intrusion detection, honeypot, redirection, extra in-depth authentication information, and practical input validation strategy. The material is designed to give you the extra edge in defending your application.

CPE/CMU Credits: 6


  • Cross-site scripting vulnerability and defenses
  • Web environment configuration security
  • Intrusion detection in web application
  • Incident handling
  • Honeytoken


DEV522.4: AJAX and Web Services Security


Day four is dedicated to the security of asynchronous JavaScript and XML (AJAX) and web services, which are currently the most active areas in web application development. Security issues continue to arise as organizations dive head first into insecurely implementing new web technologies without first understanding them.

We will cover security issues, mitigation strategies, and general best practices for implementing AJAX and web services. We will also examine real-world attacks and trends to give you a better understanding of exactly what you are protecting against. Discussion focuses on the web services in the morning and AJAX technologies in the afternoon.

CPE/CMU Credits: 6


  • Web services overview
  • Security in parsing of XML
  • XML security
  • AJAX technologies overview
  • AJAX attack trends and common attacks
  • AJAX defense


DEV522.5: Cutting-Edge Web Security


Day five focuses on cutting-edge web application technologies and current research area. Topics such as clickjacking and DNS rebinding are covered. These vulnerabilities are difficult to defend and multiple defense strategies are needed for their defense to be successful.

Another topic of discussion is the new generation of single-sign-on solutions such as OpenID. We cover the implications of using these authentication systems and the common "gotchas" to avoid.

With the Web2.0 adoption, the use of Java applet, Flash, ActiveX, and Silverlight are on the increase. The security strategies of defending these technologies are discussed so that these client-side technologies can be locked down properly.

CPE/CMU Credits: 6


  • Clickjacking
  • DNS rebinding
  • Flash security
  • Java applet security
  • Single-sign-on solution and security
  • IPv6 impact on web security


DEV522.6: Capture and Defend the Flag Exercise


Day six starts with an introduction to the secure software development life cycle and how to apply it to web development. But the focus is a large lab that will tie together the lessons learned during the week and reinforce them with hands-on applications. Students will be provided with a virtual machine to implement a complete database-driven dynamic website. In addition, they will use a custom tool to enumerate security vulnerabilities and simulate a vulnerability assessment of the website. Students will then have to decide which vulnerabilities are real and which are false positives, and then mitigate the vulnerabilities. The scanner will score the student as vulnerabilities are eliminated or checked off as false positives. Advanced students will be able to extend this exercise and find vulnerabilities not presented by the scanner.

Students will learn through these hands-on exercises how to secure the web application, starting with the operating system, the web server, finding configuration problems in the application language setup, and finding and fixing coding problems in the site.

CPE/CMU Credits: 6


  • Mitigation of server configuration errors
  • Discovering and mitigating coding problems
  • Testing business logic issues and fixing problems
  • Web services testing and security problem mitigation
  • Reinforcement through exercises of key topics discussed throughout the course.


Who Should Attend

  • Application developers
  • Application security analysts or managers
  • Application architects
  • Penetration testers who are interested in learning about defensive strategies
  • Security professionals who are interested in learning about web application security
  • Auditors who need to understand defensive mechanisms in web applications
  • Employees of PCI compliant organizations who need to be trained to comply with PCI requirements


What You Will Receive

  • A Ubuntu Linux VMWare virtual machine containing:
    • Virtual server environment consisting of a DNS, FTP, web server, and database to simulate
    • Multiple sample applications for the in-class exercises
    • Pre-installed security tools (e.g., brute forcing, manipulating proxy, and exploiting tools)
  • Course books for the six days of lecture
  • MP3 audio files of the complete course lecture


You Will Be Able To

  • Understand the major risks and common vulnerabilities related to web applications through real-world examples.
  • Mitigate common security vulnerabilities in web applications using proper coding techniques, software components, configurations, and defensive architecture.
  • Understand the best practices in various domains of web application security such as authentication, access control, and input validation.
  • Fulfill the training requirement as stated in PCI DSS 6.5.
  • Deploy and consume web services (SOAP and REST) in a more secure fashion.
  • Proactively deploy cutting-edge defensive mechanisms such as the defensive HTTP response headers and Content Security Policy to improve the security of web applications.
  • Strategically roll out a web application security program in a large environment.
  • Incorporate advanced web technologies such as HTML5 and AJAX cross-domain requests into applications in a safe and secure manner.
  • Develop strategies to assess the security posture of multiple web applications.

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