Web-Defense - client-side protection against web attacks

The Internet, and in particular the world-wide web, have become part of the everyday life of millions of people. In recent years, however, it has also turned into a hostile and dangerous place. Besides traditional attacks against web servers and web-based applications, attackers are increasingly aiming at end-users. Novel threats have emerged in which the adversaries are not only interested in taking control of remote machines, but also in stealing sensitive information from their users. A common theme among such client-side attacks, which include phishing, cross-site scripting attacks, and spyware, is that sensitive information in possession of the victim is illicitly transmitted to the attacker. That is, an unauthorized information flow from the victim to the attacker occurs. As a result, the attacker can obtain access to authentication tokens such as passwords or session cookies and personal data such as credit card or social security numbers. This information is then abused for online fraud and identity theft. Traditional attack venues such as buffer overruns or exploits of input validation errors have been known for a long time and are widely understood. As a result, a large number of defense mechanisms have been devised. For client- side attacks, however, only a few viable defense solutions have emerged so far. These techniques often focus on one particular problem area only and fail to address the larger and more general problem of unauthorized information flow attacks. In this project, we propose to develop novel client-side defense solutions that protect users from unintentional disclosure of sensitive information. The idea is to put client-side attacks into a unified context and analyze their common and distinct properties. The result is a model to characterize client-side attacks that helps to identify regions in the solution space that have not been explored so far. Based on our model, we will develop practical techniques to counter the identified threats.

The Internet, and in particular the world-wide web, have become part of the everyday life of millions of people. In recent years, however, it has also turned into a hostile and dangerous place. Besides traditional attacks against web servers and web-based applications, attackers are increasingly aiming at end-users. Novel threats have emerged in which the adversaries are not only interested in taking control of remote machines, but also in stealing sensitive information from their users. A common theme among such client-side attacks, which include phishing, cross-site scripting attacks, and spyware, is that sensitive information in possession of the victim is illicitly transmitted to the attacker. That is, an unauthorized information flow from the victim to the attacker occurs. As a result, the attacker can obtain access to authentication tokens such as passwords or session cookies and personal data such as credit card or social security numbers. This information is then abused for online fraud and identity theft. Traditional attack venues such as buffer overruns or exploits of input validation errors have been known for a long time and are widely understood. As a result, a large number of defense mechanisms have been devised. For client-side attacks, however, only a few viable defense solutions have emerged so far. These techniques often focus on one particular problem area only and fail to address the larger and more general problem of unauthorized information flow attacks. The Webdefense project aimed to develop novel client-side defence solutions that aim to protect users from unintentional disclosure of sensitive information. The idea was to put client-side attacks into a unified context and analyze their common and distinct properties. The result is a model to characterize client-side attacks that helps to identify regions in the solution space that have not been explored so far. Based on our models, we developed practical techniques to counter the identified threats.