
U.S. President Joe Biden has called on u.S. companies and private organizations to "lock their digital doors," claiming intelligence suggests Russia is planning a cyber attack on the U.S.
UK cyber authorities are also supporting White House calls for "increased cybersecurity precautions," although neither has provided any evidence that Russia is planning a cyber attack.
Russia has previously stated that such accusations are "Russophobic".
However, Russia remains a cyber superpower with a serious arsenal of cyber tools and hackers capable of destructive and potentially damaging cyber attacks. Ukraine has remained relatively undisturbed by Russian cyberattacks, but experts now fear Russia could go on a cyber offensive against its allies.
"Biden's warnings seem credible, especially as the West imposed more sanctions, hackers continue to join the conflict and kinetic aspects of the invasion apparently do not go according to plan," says Jen Ellis, from cybersecurity firm Rapid7.
Ukraine is often described as Russia's cyber playground, which has carried out attacks there apparently to test techniques and tools.
In 2015, Ukraine's power grid was disrupted by a cyberattack called BlackEnergy, which caused a short-term shutdown for 80,000 customers of a utility company in western Ukraine.
The US and EU named and blamed Russian military hackers for the attacks.
"Russia can absolutely try to execute an attack like this against the West as an illustration of capabilities and to convey a message," says Ukrainian cybersecurity expert Marina Crotofil, who helped investigate the hacks of the power outage.
NotPetya is thought to be the costliest cyber attack in history and has been blamed on a group of Russian military hackers by US, UK and EU authorities.
The destructive software was hidden in an update of the known accounting software used in Ukraine, but spread worldwide destroying the computer systems of thousands of companies and causing about $10 billion in damage. North Korean hackers are accused of using such software with a similar attack a month ago.
In May 2021, a state of emergency was declared in a number of American states after hackers caused the closure of a vital gas pipeline.
"Colonial Pipeline" carries 45 percent of the East Coast's supply of oil, gasoline and jet fuel, and supply led to panic in pumps.
This attack was carried out not by Russian government hackers, but by the ransomware group DarkSide, which is thought to be based in Russia. The pipeline company admitted that it had paid criminals $4.4 million in Hard-to-Trace Bitcoin in order to restore and function computer systems.