By FRANK BAJAK, ERIC TUCKER and MATT O'BRIEN WASHINGTON (AP) — A ransomware attack paralyzed the networks of at least 200 U.S. companies on Friday, according to a cybersecurity researcher whose company was responding to the incident. The REvil gang, a major Russian-speaking ransomware syndicate, appears to be behind the attack, said John Hammond of the security firm Huntress Labs. He said the criminals