UK firms warned of Russian cyberwar ‘spillover’ from Ukraine

British officials are concerned about "spillover" from any heightened Russian cyber-activity in Ukraine, as demonstrated by last week's attack on two banks by hackers linked to the GRU spy agency.

Although there have been no Ukraine-related Russian attacks on the UK since the start of the crisis, cyber-specialists have been holding meetings with key companies to discuss the possible threat and how it could be tackled.

"Organisations need to understand there is a heightened risk," said one official, with a particular focus on monitoring whether an intense Russian cyber-attack on Ukrainian targets could have wider consequences.

Jeremy Fleming, the head of the spy agency GCHQ, held a roundtable last week to discuss the threat with organisations responsible for Britain's "critical national infrastructure", which includes the communications, energy, food, health and transport sectors.

Ukraine has been a target for regular Russian cyber-attacks since the start of the war in 2014 and last week was hit with a "sophisticated" attack that tried to disrupt customer services at two Ukrainian banks and the website of the defence ministry.

On Friday, the NCSC, Britain's cybersecurity agency, said it believed Russia's GRU military intelligence was behind the "denial of service" attack. But although relatively serious, officials believe it was "not necessarily a precursor" for a military offensive or enhanced cyber-action.

A recent NCSC briefing, which is considered still valid, said: "While the NCSC is not aware of any current specific threats to UK organisations in relation to events in and around Ukraine, there has been an historical pattern of cyber-attacks on Ukraine with international consequences."

In 2017, Russian state actors launched the NotPetya malware against Ukrainian companies, but it spread indiscriminately around the world, affecting a string of western companies and even some Russian corporations. Western spy agencies have previously said that attack was also conducted by GRU operatives.

Ukraine's long experience in dealing with cyber-attacks - two of which, in 2015 and 2016, briefly disrupted some power supplies - means that western officials believe Kyiv is relatively experienced at picking up the pieces after a damaging attack.

Nevertheless, the UK and the US have been helping the country's cybersecurity agencies, as the crisis has intensified. On Tuesday, six EU countries said they, too, would offer further assistance.

A western official said: "We share our understanding of the threats and we have and continue to make them aware of threats."