Delta has further alleged that CrowdStrike postured as a certified best-in-class security provider who "never cuts corners" while secretly designing its software to bypass Microsoft security certifications in order to make changes at the core of Delta's computing systems without Delta's knowledge.

The lawsuit claims that the cybersecurity firm failed to do basic testing on the update which caused IT failures all over the world before rolling it out.

The battle between Delta Air Lines and CrowdStrike has escalated after both companies filed competing lawsuits against each other over the summer's tech outage and flight cancellations.