nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqphwcmqjwjkvuxy9h5flrpyc30utwgudwpcr4lvtakr77gu2lgczs0mstvl (nprofile…stvl) Unfortunately it is very difficult. But in my OpSec training I do cover a system for flagging certain behaviour patterns that can help identify and isolate an infiltrator before harm is done. But one has to be careful as false positives, and associated paranoia, can also do much harm.
I recommend studying social engineering techniques used by spy cops such that one can identify when being played. A good book on this is 'Social Engineering: The Art of Human Hacking' by Hadnagy.