It's more dangerous than some exploits, to boot. The technique is "extremely reliable," and won't give things away by crashing the computer. That's potentially useful for state-sponsored attacks where stealthiness is important.

The good news? If you're the type who updates software as soon as an upgrade is available, you're safe. SentinelOne let Apple know about the bug in January, so OS X 10.11.4 and iOS 9.3 (conveniently released this week) both contain patches for it, although if you're on an older version of OS X you are still potentially vulnerable. Having said this, the flaw remains a warning that SIP is merely another layer of defense, not a catch-all -- it still helps to be vigilant and prevent this rogue code from touching your device in the first place.