US cybersecurity firm CrowdStrike which was responsible for the crippling outage last month that affected millions of Microsoft computers worldwide and caused hundreds of millions of damages among businesses affected by that incident is now being sued by its investors.

Shareholders have now filed a class action lawsuit against CrowdStrike accusing the company of making “false and misleading” statements about its software testing.

The suit filed in the Austin, Texas federal court, alleges that CrowdStrike executives defrauded investors by making them believe the company’s software updates were adequately tested.

It cites chief executive George Kurtz, who said in a conference call on March 5, that the firm’s software was “validated, tested and certified.”

The lawsuit seeks an unspecified amount of compensation for investors who owned CrowdStrike shares between November 29 and July 29. The company’s share price dropped 32 per cent in the 12 days after the incident, causing a loss in market value of $25bn (A$38.49 billion).

Crowdstrike

“We believe this case lacks merit and we will vigorously defend the company,” a spokesperson told BBC.

Some of the customers worst affected by the outage, including Delta Air Lines, are now reported to be rethinking their relationship with Microsoft and CrowdStrike.

Delta Air Lines CEO Ed Bastian said the outage cost his company half a billion dollars in five days and resulted in the airline being forced to cancel more than 5,000 flights. Bastian noted that costs included more than 40,000 servers that “we had to physically touch and reset” as well as compensation payments that had to be made out to travellers.

Asked in an interview with CNBC about a continuing relationship with Microsoft post the crash, Bastian asked, “When was the last time you heard of a big outage at Apple?”

Bastian also criticised the flaw that caused the outage and CrowdStrike’s deployment processes, saying, “If you’re going to have priority access to the Delta ecosystem… you’ve got to test this stuff. You can’t come into a mission-critical, 24-7 operation and tell us, ‘We have a bug.’ It doesn’t work.”

Delta is reported to have hired attorney David Boies to seek damages.