National roaming services for Kyivstar subscribers were temporarily blocked at the request of the the Security Service of Ukraine (SSU). This was done to avoid overloading other operators.
Why national roaming does not work for Kyivstar subscribers
The National Centre for Operational and Technical Management of Telecommunication Networks of the State Service for Special Communications ordered to temporarily block national roaming for Kyivstar subscribers. This was done at the request of the SSU.
The blocking will help avoid overloading other operators' networks. Therefore, subscribers will not be able to switch to them for the time being.
Specialists of the Governmental Computer Emergency Response Team CERT-UA, the Security Service and Kyivstar are investigating the cyber incident.
What is known about the cyber attack on Kyivstar
A large-scale technical failure in Kyivstar's network occurred in the morning of 12 December. Subscribers cannot switch to other operators via national roaming, and communication and the Internet are down. Some PrivatBank terminals and ATMs are also experiencing problems. DTEK, the largest commercial energy operator in Ukraine, reported that its contact centre numbers in Kyivstar's network are not working.
On that day, the Security Service opened a case over the hacker attack on Kyivstar under eight articles. According to one version of the investigation, Russian special services may have been involved in the hacker attack on Kyivstar. Cyber experts are coordinating the efforts of all government agencies to restore the network as soon as possible.
Later, it turned out that the Russian Federation's GRU might be behind the attack on Kyivstar. The Russian hacker group Solntsepek claimed responsibility.
Currently, the company's specialists are working to restore other services and will do everything possible to complete these works by 13 December 2023.
American companies Microsoft, Cisco and Sweden's Ericsson are helping Ukrainian mobile operator Kyivstar to resume operations after a large-scale cyber attack.
According to the SSU’s preliminary estimates, the mobile operator will restore fixed-line internet for households and launch mobile and internet services on 13 December.
After the network is stabilised, all subscribers and corporate clients who were unable to use the company's services due to the hacker attack will receive compensation.
