GWT interfering with XSS preventative measures.

Question

I'm currently in the process of developing a GWT 1.7.1 application that deals with a significant amount of persistent, user generated data so there is a risk of malicious XSS. One of the steps I am taking to prevent this is using org.apache.commons.lang.StringEscapeUtils.escapeHtml() server-side (Yes I am well aware that this will not prevent all possible XSS attacks as mentioned here and here).

This approach is causing a client-side problem since it appears that GWT is performing it's own client-side escaping (e.g. The server returns the string “Alice & Bob Inc.” and “Alice & Bob Inc.” is being rendered to the DOM which is incorrect). This is definitely happening client-side as the http response from the server contains the correctly encoded data. I have been going through the documentation for GWT and haven't found any reference to this feature. Is anyone aware of a way of disabling this behaviour?

Answer 1

How are you adding the value the server returns to the page? Could you be adding at as text? If you are sure the String is safe you can add it as HTML (there is usually an option for HTML) or specific Widgets like HTML.

btw Usually best not to return HTML encoded values from the server as you don't know how you may want to use them. I use the rule that you keep the values in their clean format till the last minute (adding to the document etc).