Sinclair Broadcast Group, one of the largest TV station operators in the US, said Monday that a ransomware incident had disrupted some of its office and operational networks.

“[T]he event has caused — and may continue to cause — disruption to parts of the company’s business, including certain aspects of its provision of local advertisements by its local broadcast stations on behalf of its customers,” the company said in a press release posted to the Securities and Exchange Commission website.

[Sinclair operates two stations in the Triangle – WRDC and WLFL.]

Sinclair began investigating the incident on Saturday, and on Sunday identified “certain servers and workstations in its environment were encrypted with ransomware,” the statement said.

The unidentified hackers also stole data from Sinclair’s network; the company said it was working to determine what information was taken. Sinclair said it had notified law enforcement and US government agencies, and that it was working to “restore operations quickly and securely.”

Sinclair owns 185 television stations in 86 markets, according to its website.

TV shows at Sinclair-owned stations in parts of the country reported technical difficulties Sunday, with some programs struggling to go on air.

Kristin Bien, a weekend anchor at Sinclair-owned WSBT 22, tweeted Sunday morning that the incident was a “corporate-wide problem.”

“All we are told right now is that we have technical difficulties,” one journalist at a Sinclair-owned station told CNN Sunday night. “We are still told to broadcast if we can, so we’re doing what we can with our live unit and weather graphics. We don’t have access to our company emails or anything that requires a company log in.”

Ransomware — malicious software that locks computer networks until victims pay a fee — has been a threat to US businesses for years. But it became a national security priority for the Biden administration after a series of ransomware incidents disrupted US critical infrastructure firms this year.

This isn’t the first time that a cybersecurity incident has hobbled a prominent TV broadcaster.

Australia’s 9 News network in March said a cyberattack disrupted its live broadcasts. And in the US, local stations owned by the Cox Media Group were hit in June.

The Record, a cybersecurity news outlet, was first to report on the ransomware incident at Sinclair.

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