Cyber Incident Victim: Sinclair Broadcast Group
Date:
Oct 2021
Location:
United States of America
Summary
A ransomware attack severely disrupted operations across numerous US television stations owned by Sinclair Broadcast Group, impacting corporate Active Directory services and causing widespread technical failures. The incident encrypted devices, exfiltrated data, and crippled critical systems including email servers, broadcasting infrastructure, and newsroom operations, forcing affiliates to adopt temporary solutions like Gmail accounts and PowerPoint for graphics. Broadcast schedules were significantly altered, with some stations substituting regular programming—including local NFL games—with national sports content or alternative channels, while others canceled or shortened newscasts entirely. The company engaged cybersecurity experts, notified law enforcement, and implemented business continuity protocols to contain the breach and restore services, though residual issues like malfunctioning weather graphics persisted at several stations during recovery efforts.
| CIA Posture | Motives | Tactics, Techniques & Procedures |
|---|---|---|
| Available to members | 1 motive | 2 techniques |
| Threat Actor | Type | Location |
|---|---|---|
| 1 actor | Available to members | Available to members |
Description
On October 16, 2021, Sinclair Broadcast Group (SBGI), a Fortune 500 media conglomerate operating 185 television stations across 87 U.S. markets, experienced a ransomware attack that severely disrupted broadcasting operations nationwide. Attackers compromised the company's corporate Active Directory domain, enabling them to disrupt critical infrastructure across Sinclair's network of affiliates, which reached nearly 40% of U.S. households. This marked the second cybersecurity incident affecting Sinclair in 2021, following a July breach that prompted company-wide password resets. The ransomware attack forced Sinclair to shut down Active Directory services, blocking access to domain resources and causing cascading failures. Email servers, broadcasting systems, and newsroom operations were taken offline, compelling local stations to adopt emergency workarounds—including creating Gmail accounts for viewer news tips and using PowerPoint for newscast graphics. While regional sports networks remained largely operational, some markets replaced local NFL game broadcasts with national programming like bowling. Multiple stations resorted to Facebook livestreams for newscasts, while others canceled evening broadcasts entirely, including WTAT and WRGB stations.
Sinclair confirmed the ransomware attack in an October 18 press release and SEC filing, disclosing that attackers had encrypted devices, exfiltrated data, and disrupted business operations. Senior management activated incident response and business continuity protocols, engaged a cybersecurity firm with ransomware experience, and notified law enforcement agencies. Containment measures were implemented, though restoration efforts progressed unevenly across affiliates. By October 18, stations like KABB and WCHS resumed broadcasting but faced persistent technical issues—KABB struggled with weather graphics, while WCHS streamed Fox NewsEdge content via a browser window. Stations including WBSF and WCWN substituted regular CW programming with "Charge!" subchannel content, and WPFO truncated its newscast from one hour to thirty minutes. The incident investigation remained ongoing, with Sinclair pledging to enhance security measures based on findings. Operational disruptions highlighted the attack's scale, affecting news production, advertising, and local programming distribution through critical infrastructure compromises.