“The malware involved in this incident is designed to infiltrate, encrypt files, and disrupt business,” the statement said today. The company did not use the phrase ransomware, which had been the suspect attacker. Many online messages on a thread on Reddit mentioned the MegaCortex strain which has been attacking businesses worldwide

WK detected problems on May 6 and took down most applications and platform, including its VoIP system. The outage was widespread for three days with some systems still down over through the weekend. "We have now restored service to nearly all customer applications and platforms," it said in its May 16 statement.

Steps taken after that include having anti-virus vendors provide updated detection files The company also brought systems and applications back online cautiously.

“This process involved system-by-system and application-by-application assessment, scanning, testing, and quality assurance protocols designed to provide protections that when we return to service, we do so in a safe and secure way,” the statement said.