F-Secure says it can not prove which country was behind the hack but the group had links to 'entities ' in China , Russia and Ukraine The UK Foreign Office was targeted by a group of determined and well-funded hackers over several months last year . Research published by cybersecurity firm F-Secure suggested the attack was a “ spear-phishing Attack.Phishing ” campaign in which people are sent Attack.Phishing targeted emails with a link to a false login page to trick Attack.Phishing users into giving up their username and password . The hackers created Attack.Phishing websites that looked like Attack.Phishing legitimate Foreign Office websites , including those for accessing an internal email account online . The scam is believed to have been perpetrated by hackers who call themselves the Callisto Group . F-Secure said it did not know whether the attack was successful and the National Cyber Security Centre did not say whether data had been stolen Attack.Databreach . It was discovered after the spy agency analysed a successful attack on the French broadcaster TV5Monde in 2015 . The group forced the channel ’ s scheduled programming off air for 18 hours and replaced them with a screen showing the terror group ’ s flag . The inference with the UK ’ s government follows on from an ongoing probe into the Kremlin ’ s influence on the US elections last year . Hacking groups such as DC Leaks , Fancy Bears and Guccifer 2.0 who were responsible for the leaking Attack.Databreach of damaging information about the Democrat party . The most significant attack Attack.Databreach , the leaking Attack.Databreach of thousands of private emails between senior members of the DNC to Wikileaks by Fancy Bears , lead to the resignation of DNC Chair Debbie Wasserman-Schultz .