This looks like a repeat of a story I posted a while ago, but maybe there are more details (https://herereadthisarticle.wordpress.com/2018/08/16/botched-cia-communications-system-helped-blow-cover-of-chinese-agents-foreign-policy/). (I haven’t fully read it yet.)
«From around 2009 to 2013, the U.S. intelligence community experienced crippling intelligence failures related to its secret internet-based communications system, a key means for remote messaging between CIA officers and their sources.»