UK intel: Cyber attack on Kyivstar one of highest-impact disruptive cyber attacks since war started

British intelligence has called a recent cyber attack on Kyivstar, Ukraine's largest mobile network operator, as one of the highest-impact disruptive cyber attacks on Ukrainian networks since the start of Russia's full-scale invasion.

The UK Defense Ministry said this in an intelligence update on the X social media platform, Ukrinform reports.

On December 12, 2023, Kyivstar suffered a cyber attack. Effects continued for at least 48 hours, impacting the company's mobile and data services. The cyber attack reportedly left over half of Ukraine's population without mobile signal or the ability to use the internet. Kyivstar reported that no personal data was compromised during the attack.

The cyber attack also reportedly disrupted air raid sirens, some banks, ATMs, and point-of-sale terminals. At the same time, the Ukrainian bank Monobank, was targeted with a Distributed Denial of Service (DDoS) attack, disrupting access to the bank's website.

"With Ukraine's government resources and emergency services affected, this incident is likely one of the highest-impact disruptive cyber attacks on Ukrainian networks since the start of Russia's full-scale invasion," intelligence experts said.