 OLDWICK, N.J.--BUSINESS WIRE--AM Best has commented that the Credit Ratings ratings of CNA Financial Corporation CNAF NYSE:CNA and its insurance subsidiaries remain unchanged following the companys disclosure that it sustained a sophisticated cybersecurity attack that caused a network disruption and impacted certain CNAF systems, including corporate email. The outlook of these ratings is stable. Based on the information available as of today, AM Best believes that the company is workin 