The Russian government is allegedly behind the data breach affecting the U.S. court filing system known as PACER, according to The New York Times.

Citing anonymous sources, the newspaper said Russia “is at least in part responsible” for the cyberattack, without saying what part of the Russian government is behind the hack.

The hackers searched for “midlevel criminal cases in the New York City area and several other jurisdictions, with some cases involving people with Russian and Eastern European surnames,” per the article. 

Last week, Politico reported that hackers had broken into the federal judiciary’s electronic case filing system, potentially accessing the identities of confidential informants, which are redacted and not publicly known, putting those people at risk of retaliation from the criminals they are helping authorities apprehend. 

Politico reported that the stolen data could include sealed criminal dockets and indictments, arrest warrants, and other documents not yet public, or may never actually be included in public dockets. 

The Administrative Office of the U.S. Courts, the agency that oversees the U.S. federal court system, confirmed a cyberattack in a statement on August 7.

The New York Times also quoted a memo sent to Justice Department officials, clerks, and chief judges by the court system’s administrators, which said that “persistent and sophisticated cyber threat actors have recently compromised sealed records.” The email said “this remains an URGENT MATTER that requires immediate action.”

This may not be Russia’s first rodeo targeting the U.S. federal court system. 

In 2020, a long-running Russian cyberattack targeted the SolarWinds software, used by large tech companies and government agencies, to deliver a tainted software update allowing Russian government hackers backdoor access to the networks of SolarWinds customers. 

The widespread hack affected several U.S. government departments, including PACER, allowing the theft of sealed court documents.

The U.S. Courts, in its statement on August 7, said that the agency was “enhancing security of the system and to block future attacks, and it is prioritizing working with courts to mitigate the impact on litigants.”