Attackers hacked the cyber defenses of the largest Ukrainian mobile operator Kyivstar through a compromised account of one of its employees, Kyivstar President Oleksandr Komarov said during a national telethon on Wednesday.

"We must admit that this attack penetrated our defense. This happened because the account pool was compromised, the account of one of the employees was compromised, and the enemy was able to get inside the company's infrastructure. An investigation into this is underway," Komarov said, adding that he is not yet aware of the findings of the investigation.

The president of Kyivstar noted that the issue is not technology, but the fact that in any organization there may be people who "conditionally aim Russian missiles or give away their passwords because social engineering works well."

The company used the most modern technologies to protect against cyber threats and, since the beginning of the full-scale invasion, has repulsed about 500 cyber attacks, Komarov said.

"Look, it seems to me that the example of Kyivstar shows that even the most secure infrastructure can be affected. It's real. We use the latest technologies from global suppliers to keep the company's perimeter closed from cyber threats. This is not the first year that we have been faced with a threat... since the beginning of the war, we have repulsed approximately 500 more or less serious attacks," he said.

The attack was made by the Russian hacker group Solntsepek, which, according to the Security Service of Ukraine, is close to the main intelligence directorate of the General Staff of the Russian Forces (formerly GRU).

"They did this to lay down the largest telecommunications infrastructure in the country, in order to sow trouble, emotionally shock Ukrainians... there is a war going on – this is one of the ways of war against Ukraine," the president of Kyivstar said.