Fingerprinting by detecting CanvasBlocker

PoC: https://jsfiddle.net/6ke4ycmb/

In case you don’t want to click a link and execute my JS here’s the code:

var canvas = document.createElement('canvas');
var ctx = canvas.getContext("2d");
var canvasBlocker=false;
try{
	ctx.getImageData(0,0,0,0);
}catch(err){
	try{
		console.log(err.name);
  }catch(err2){
  	canvasBlocker=true;
  }
}
if(canvasBlocker){
	alert("Canvas blocker detected.");
}else{
	alert("No canvas blocker detected");
}

This reliably recognized if CanvasBlocker is in use in my tests. Thus providing another bit for fingerprinting 😦

Not sure how exactly this can be fixed though, as I’m not familiar with Firefox Extensions.

[kkapsner]

Finally got rid of the technical problems there. The picture will remain like that in the future.

[kkapsner]

Some upvotes can’t hurt. But I think all their ressources are blocked by the move to webExtensions. There are still APIs missing.