I've gotten attacked by the infamous "Pharma" hack twice in the past week. Not sure the cause, but I've noticed that when the attacker strikes, WordPress complains that a WP Super Cache PHP file was deleted. Unfortunately, the error only appears once so I don't remember the exact file name.
The attack leaves a file called uploas.php in wp-includes that redirects bots to a pharmaceutical website.
I don't know if this is a vulnerability caused by WP Super Cache, but I figured it's worth pointing out. In the meantime, I'm going to keep looking into it.