Chrome: ERR_BLOCKED_BY_XSS_AUDITOR details

Question

I'm getting this chrome flag when trying to post and then get a simple form.

The problem is that the Developer Console shows nothing about this and I cannot find the source of the problem by myself.

Is there any option for looking this at more detail? View the piece of code triggering the error for fixing it...

Answer 1

The simple way for bypass this error in developing is send header to browser

Put the header before send data to browser.

In php you can send this header for bypass this error ,send header reference:

header('X-XSS-Protection:0'); 

In the ASP.net you can send this header and send header reference:

HttpContext.Response.AddHeader("X-XSS-Protection","0"); or  HttpContext.Current.Response.AddHeader("X-XSS-Protection","0");  

In the nodejs send header, send header reference :

res.writeHead(200, {'X-XSS-Protection':0 }); // or express js res.set('X-XSS-Protection', 0); 

Answer 2

Chrome v58 might or might not fix your issue... It really depends to what you're actually POSTing. For example, if you're trying to POST some raw HTML/XML data whithin an input/select/textarea element, your request might still be blocked from the auditor.

In the past few days I hit this issue in two different scenarios: a WYSIWYG client-side editor and an interactive upload form featuring some kind of content preview. I managed to fix them both by base64-encoding the raw HTML before POSTing it, then decoding it on the receiving PHP page. This will most likely fix the issue and, most importantly, increase the developer's awareness level regarding the data coming from POST requests, hopefully pushing him into adopting effective data encoding/decoding strategies and strengthen their web application from XSS-type attacks.

To base64-encode your content on the client side you can either use the native btoa() function, which is supported by most browsers nowadays, or a third-party alternative such as a jQuery plugin (I ended up using this, which worked ok).

To base64-decode the POST data you can then use PHP's base64_decode(str) function, ASP.NET's Convert.FromBase64String(str) or anything else (depending on your server-side scenario).

For further info, check out this blog post that I wrote on the topic.