The UK government has accused Russia's military intelligence service of being behind four high-profile cyber attacks.
The National Cyber Security Centre says targets included firms in Russia and Ukraine; the US Democratic Party; and a small TV network in the UK.
World Anti-Doping Agency computers are also said to have been attacked.
Files later emerged showing how British cyclists Sir Bradley Wiggins and Chris Froome had used banned substances for legitimate medical reasons.
At the time, some of the attacks were linked to Russia - but this is the first time the UK has singled out the GRU, the Russian military intelligence service.
British police think the men who carried out the Salisbury poisoning in March worked for the same group.
The NCSC said it has assessed "with high confidence" that the GRU was "almost certainly responsible" for the cyber attacks.
Foreign Secretary Jeremy Hunt said the GRU had waged a campaign of "indiscriminate and reckless" cyber strikes that served "no legitimate national security interest".
Cyber security consultant Andrew Tsonchev said individuals can get "caught up" in the attacks.
He said: "The more obvious and urgent effect that people need to be aware of is that the services they use - the essential services - are at risk and are actively being targeted for sabotage."