"I know they have the ability to do at least as much damage as they did in Estonia and Georgia," he said.
Estonia suffered a 10-day attack on its Internet services in 2007, which caused major disruptions to its financial system, during a spat with Moscow over a Soviet-era war memorial, and Georgia was hit by mass cyberattacks during a brief 2008 war with Russia over its pro-Moscow South Ossetia region.
Russian authorities denied direct involvement in both attacks, saying they had no influence over the actions of self-styled patriotic hackers.
Russia holding back?
Much of Ukraine's telecommunications infrastructure was built when it was part of the Soviet Union, along with what is now the Russian Federation, and is particularly vulnerable to penetration by Moscow.
"The Russians have the place completely wired," said Jim Lewis, a former U.S. foreign service officer and now senior fellow at the Center for Strategic and International Studies in Washington.
"They are right next door and most traffic has to go through Russia. That they haven't done more probably reflects their confidence that they're going to come out ahead and there's nothing anyone can do about it," Lewis said.
Cyberwarfare experts say that while Russia certainly has the ability to conduct such campaigns against Ukraine, it has yet to need to use those capabilities.
"This would show the Russians acting with more discretion and targeting than recently," said John Bassett, former head of the London and Washington stations of GCHQ, Britain's top secret government communications center.
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"This wouldn't expose any great depth of their technological capability and they would be keeping the harder stuff back," said Bassett, now associate at Oxford University's Cyber Security Centre.
Marty Martin, a former senior operations officer with the CIA, said Moscow would likely only take action to damage Ukraine's Internet and internal communications systems if hostilities broke out.
"A lot of times you don't want to shut things down. If you do that, then you don't get your flow of intelligence. You are probably better off monitoring it," Martin said.
Experts believe Russia was behind the hacking of a confidential phone conversation between senior U.S. State Department official Victoria Nuland and U.S. Ambassador to Ukraine Geoffrey Pyatt, which was leaked over YouTube last month.
"Russia's strategy is control the narrative, discredit opponents, and coerce," Lewis said.