Old sentence was grammatically incorrect, literally meant that the URL or button in question did not know it was redirecting the user.  It is the user who does not know, so "unwittingly" is replaced with "secretly"; "surreptitiously" would be another accurate alternative.  An alternative sentence construction that maintains the word "unwittingly" would be, e.g., "...might click on a URL or button on another website and be unwittingly redirected to your application to perform some command that requires elevated privileges."