Apple Testflight Spam in USER_IN_DEF_DKIM_WL and USER_IN_DEF_SPF_WL

[Matt Corallo]

It seems people are now spamming testflight invites at random and bypassing SA due to the combo of 
the DKIM_WL and SPF_WL for mail from testflight_no_re...@email.apple.com.