Several years after their widespread adoption, web applications on the Internet today are still rife with vulnerabilities. Understanding of the security threats facing web applications, and effective ways of addressing these, remains immature within the industry. There is currently little indication that the problem factors described previously are going to go away in the near future.
That said, the details of the web application security landscape are not static. While old and well understood vulnerabilities like SQL injection continue to appear, their prevalence is gradually diminishing. Further, the instances that remain are becoming more difficult to find and exploit. Much current research is focused on developing advanced techniques for attacking more subtle manifestations of vulnerabilities which a few years ago could be easily detected and exploited using only a browser.
A second prominent trend is a gradual shift in attention from traditional attacks against the server side of the application to those that target other users. The latter kind of attack still leverages defects within the application itself, but it generally involves some kind of interaction with another user, to compromise that user’s dealings with the vulnerable application. This is a trend that has been replicated in other areas of software security. As awareness of security threats matures, flaws in the server side are the first to be well understood and addressed, leaving the client side as a key battleground as the learning process continues. those against other users are evolving the most quickly, and are the focus of most current research.