An off-path attacker can cause a preemptable client association to be demobilized by sending a crypto NAK packet to a victim client with a spoofed source address of an existing associated peer. This is true even if authentication is enabled. Furthermore, if the attacker keeps sending crypto NAK packets, for example every one second, the victim never has a chance to reestablish the association and synchronize time with the legitimate server. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-1547
