Posted on by Achim D. Brucker, licensed under CC BY-ND 4.0.

The Evil Friend in Your Browser

On the one hand, browser extensions, e.g., for Chrome, are very useful, as they extend web browsers with additional functionality (e.g., blocking ads). On the other hand, they are the most dangerous code that runs in your browsers: extension can read and modify both the content displayed in the browser. As they also can communicate with any web-site or web-service, they can report both data and metadata to external parties. The current security model for browser extensions seems to be inadequate for expressing the security or privacy needs of browser users. Consequently, browser extensions are a “juice target” for attackers targeting web users.

If you want to learn more, visit our talk at the OWASP AppSecEU in Belfast. Update: you can also watch the recording of our talk!.

In our talk, we present results of analyzing over 2500 browser extensions on how they use the current security model and discuss examples of extensions that are potentially of high risk. Based on the results of our analysis of real world browser extensions as well as our own threat model, we discuss the limitations of the current security model form a user perspective. need of browser users.

Supplementary Material