Well apparently javascript can be used to modify the favicon dynamically: https://stackoverflow.com/questions/260857/changing-website-favicon-dynamically https:

Well apparently javascript can be used to modify the favicon dynamically: https://stackoverflow.com/questions/260857/changing-website-favicon-dynamically https://stackoverflow.com/questions/260857/changing-website-... - presumably this will then have the same interactions with the cache. Perhaps you could just rely on the user navigating across a number of pages on your attack site.