The head of Ukraine's Cyberpolice, Colonel Serhiy Demydiuk, told media on July 3 that Kyiv-based M.E. Doc's employees had blown off repeated warnings that their information-technology infrastructure was not secure, RFE/RL reported.
"They knew about it," he told AP. "They were told many times by various antivirus firms... For this neglect, the people in this case will face criminal responsibility."
"We have issues with the company's leadership, because they knew there was a virus in their software but didn't do anything... If this is confirmed, we will bring charges," Demedyuk told Reuters.
But the father and daughter team that run the company, Olesya Linnik and her father, Serhiy, told Reuters their popular tax software, M.E.Doc, was not responsible for spreading the virus and they didn't understand the charges against them.
"We studied and analyzed our product for signs of hacking. It is not infected with a virus and everything is fine, it is safe," Olesya said. "The update package, which was sent out long before the virus was spread, we checked it 100 times and everything is fine."
"We built this business over 20 years. What is the point of us killing our own business?" Serhiy Linnik asked.
Read alsoSBU says Russian special services involved in large-scale cyber attackDemydiuk and other officials say last week's unusually disruptive cyberattack was mainly spread through a malicious update to M.E. Doc, which is widely used by accountants and businesses across Ukraine.
The malicious update, likely planted on M.E. Doc's update server by a hacker, was then disseminated across the country before exploding into an epidemic of data-scrambling software that organizations around the world are still recovering from.
Olesya Linnik said her company was cooperating with investigators and the police.
"The cyberpolice are currently bogged down in the investigation. We gave them the logs of all our servers and there are no traces that our servers spread this virus," she told Reuters.
Ukrainian authorities have blamed Russia for masterminding the outbreak, but independent experts say it's too early to come to any firm conclusions. Ukraine has repeatedly come under fire from cyberattacks linked to Moscow.