The spy group, known as Serniya Network, had previously been accused by the U.S. of illegally procuring sensitive information for the Russian military.
Exploiting a security flaw in a widely used commercial software product, the SolarWinds hack first revealed in December eventually compromised nine U.S. federal agency networks and hundreds of private commercial networks as well.
President Biden last month expelled 10 Russian diplomats and imposed new sanctions on Moscow in response to the SolarWinds breach and to suspected meddling by Moscow in the 2020 U.S. presidential election. Among the nearly three dozen individuals targeted by the sanctions was Alexei Gromov, a deputy chief of staff in the office of Russian President Vladimir Putin.
The SolarWinds incident and the general deterioration of bilateral relations are likely to be prime topics of a planned summit sometime next month between Mr. Biden and Mr. Putin, at a site likely in Europe still being negotiated.