A cyberattack has disrupted operations at Delta, a Russian provider of alarm and security systems for homes, businesses and vehicles, causing widespread service outages and a wave of customer complaints.

Delta said on Monday that it had been hit by a “large-scale, coordinated and well-organized” cyberattack that originated from an unspecified “hostile foreign state.” The company acknowledged temporary disruptions to some services but said there was no evidence that customers’ personal data had been compromised.

“Our architecture was unable to withstand a well-coordinated attack coming from outside the country,” Delta marketing director Valery Ushkov said in a video address, adding that restoring backups was taking time as the company remained under the threat of followup attacks.

The company said its technical team was working to restore its systems and expected a full recovery soon. As of Tuesday, Delta’s website and phone lines remained offline, forcing the company to communicate with tens of thousands of customers through its page on the social media platform VKontakte.

The disruption has had tangible consequences for customers. Russian-language Telegram news outlet Baza reported that users began complaining shortly after the incident that their car alarm systems could not be turned off, or that vehicles could not be unlocked at all.

Russian newspaper Kommersant reported that despite Delta’s assurances that most services were operating normally, users continued to describe widespread failures — including remote vehicle start systems malfunctioning, car doors locking unexpectedly, and engines shutting down while in motion. 

Customers also reported alarm systems in homes and commercial buildings switching to emergency mode and becoming impossible to deactivate. Recorded Future News could not independently verify those reports.

While Delta insists no customer data was leaked, an unidentified Telegram channel — which claims to be run by the hackers behind the attack — published an archive it alleges contains stolen data. The authenticity of the material and the identity of the attackers could not be independently verified.

The incident came on the same day as a separate large-scale IT outage hit booking and check-in systems used by Russian airlines and airports. Russian carriers reported temporary disruptions to ticket sales, check-in, rebooking, and refunds after problems were detected in several aviation IT systems.

Russian authorities said that outage was caused by an internal technical failure at Sirena-Travel, which operates systems used across the air travel industry, and did not attribute it to a cyberattack. Sirena-Travel has previously been targeted by hackers, including a breach of its Leonardo flight reservation system in 2023.