United States officials say a malware code associated with Russian hackers has been detected within the system of a utility in Vermont, the Washington Post reported on Friday.

While the code was not used to “disrupt” the utility’s function, the presence of the malware code indicates a worrying and “potentially serious” weak spot in the security of the national electrical grid, according to the Post. Disruptions to the electrical grid could potentially wreak havoc on “medical and emergency services” across the country.

Officials told the Post the intentions behind the hack, which is believed to have been orchestrated by a hacking operation the Obama administration has named “Grizzly Steppe,” are still unclear. But they said the presence of the malware may have been a “test” to see whether the Russian hackers could successfully infiltrate the system.

Russia has previously been accused of successfully disrupting electrical service in the Ukraine by hacking into the power grid there, CBS News reported earlier this month — included one suspected attack which left “nearly a quarter of a million people” without power in Ukraine’s Ivano-Frankivsk region.

“We can’t just look at the Ukraine attack and go ‘oh we’re safe against that attack,'” Rob Lee, a former cyber warfare operations officer in the U.S. military, told CBS News earlier this month.

“Even if we just lose a portion, right? If we have New York City or Washington D.C. go down for a day, two days, a week, what does life look like at that point?”

Source: CDN