Dutch intelligence was so deep into Cozy Bear they had their surveillance cameras
The Cozy Bear hackers are in a space in a university building near the Red Square. The group's composition varies, usually about ten people are active. The entrance is in a curved hallway. A security camera records who enters and who exits the room. The AIVD hackers manage to gain access to that camera. Not only can the intelligence service now see what the Russians are doing, they can also see who's doing it. Pictures are taken of every visitor. In Zoetermeer, these pictures are analyzed and compared to known Russian spies. Again, they've acquired information that will later prove to be vital.