Education Track: What Developers Should Know on Web Application Security

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Track Overview

Application security is an essential component of any successful project; this includes web applications, open source PHP applications, web services and proprietary business web sites.

Web application security education and awareness is needed throughout the entire development and deployment organization. Each area and level of development or deployment organizations have specific needs and requirements regarding web application security education. A manager needs other information than a security professional or developer. Novices to the profession require other training than people with several years of experience.

The OWASP Education project aims to provide in building blocks of web application security information. These modules can be combined together in education tracks targeting different audiences.

This Education Track provides in a 4 hour session covering what developers should know on web application security. It starts with an explanation of web application security and why it is important. Then the OWASP Top 10 is used to explain the nastiest vulnerabilities and how these can be prevented or remediated. A secure coding initiative must deal with all stages of a program’s lifecycle. Secure web applications are only possible when a secure SDLC is used. The SDLC is explained from the standpoint of people, processes and tools. Finally the track finishes with an exhaustive list of web application security resources for web application developers.

Track Audience

The track audience is web application developers unaware there are security issues with contemporary web applications. No prior knowledge of web application security is assumed nor necessary. This track is independent of the coding language or web frameworks used; like PHP, JSF, Java EE or .NET.

We must realize that web application developers are only one link - albeit an important one - of the chain that represents the security of a web application. This track aims to make that link as secure as possible, given the constraint of 4 hours.

Another important aspect is that web application security should be tailored to the risk profile of an organization and the specific development environment of that organization.

Table of Contents Proposal

The challenge is to cover web application security in 4 hours to a web application developer. This is presented in such a way that the developers will be able to recognize and correct web application vulnerabilities in their projects.

  • Why WebAppSec matters
This part is the introduction of the track. It identifies the current security problems with web applications. During the introduction a definition of web application security is given. Trends that are influencing the current state of web application insecurity are also explained.
  • What goes wrong
  • WebAppSec Defined
  • Current trends
  • OWASP Top 10 Introduction & Remedies
The primary aim of the OWASP Top 10 is to educate developers, designers, architects and organizations about the consequences of the most common web application security vulnerabilities. The Top 10 provides basic methods to protect against these vulnerabilities.
  • Cross Site Scripting (XSS)
  • Injection Flaws
  • Malicious File Execution
  • Insecure Direct Object Reference
  • Cross Site Request Forgery (CSRF)
  • Information Leakage and Improper Error Handling
  • Broken Authentication and Session Management
  • Insecure Cryptographic Storage
  • Insecure Communications
  • Failure to Restrict URL Access
  • Embed within SDLC (People, Processes & Tools)
There is no silver bullet when it comes to securing web applications. This problem has to be addressed from different angles, covering the involved actors, processes: development as well as deployment and Techologies.
  • People Awareness and Education
  • Development WebAppSec Controls
  • Deployment WebAppSec Controls
  • WebAppSec Tools
  • Good Secure Development Practices

Some best practices, covering e.g.

  • Validating User Input
  • Appropriate use of HTTP vs. HTTPS
  • Hiding Sensitive information from Error Messages (500 Errors)
  • Appropriate use of GET vs. POST
  • Limitation of resources and privilege (anti-DoS)
  • Providing Session/Data Persistence (Leak another user's data into your session)
  • Limited # of login attempts before temporary (15-30min) account lock
  • Secure Connection to Database (prevent compromise web host and attack database)
  • Placement of web servers (use SSL-terminating reverse proxies in the DMZ to allow URL normalization/sanitizing and HTTP forwarding through firewall into private subnet holding webserver cluster - allows for IDS/IPS pre/post secondary firewall, due to HTTPS connections terminating on the reverse proxy - e.g. Pound, Apache proxy mode, etc)
  • Throttling on a per-session basis to prevent DoS from single host.
  • Sufficient entropy source so an attacker cannot easily deplete the pool, allowing for guessable SSL keys.
  • Proper rejection of retrieval attempts against protected files (e.g. application framework file requests outside the context of the application usage should return 404 Not Found)
  • Possible use of encrypted cookies
  • Good WebAppSec Resources (not limited to OWASP)
This 4 hour education track in only the beginning of your yourney. Web application security is a moving target. New vulnerabilities and threats are discovered regularly. Web application security controls are becoming mature. The following resources should provide you with enough pointers to serve both as reference and for further research.
  • Hard Copy
  • Web Sites
  • Mailing lists
  • Blogs
  • RoundUp