In September 2008, Herman Simm, an Estonian defense ministry official and Estonia's liaison with NATO, was arrested for allegedly passing NATO classified information to Russia. The U.K. Times is reporting that some of that information included NATO cyber security strategies:
"...Mr Simm was not some relic from the days of Kim Philby or other notorious deep-cover agents. He was at the cutting edge of one of Nato’s most important new strategic missions: to defend the alliance against cyber-attack.
"Mr Simm headed government delegations in bilateral talks on protecting secret data flow. And he was an important player in devising EU and Nato information protection systems."
Russian spy in Nato could have passed on missile defence and cyber-war secrets