U.S. President Joe Biden asked Russian President Vladimir Putin on Wednesday how he would feel if someone carried out a ransomware attack on Russian oil pipelines, a pointed question during their summit that illustrated the breadth of their disagreements. The query referred to a cyberattack that closed the Colonial Pipeline Co system for several days in May, preventing millions of barrels of gasoline, diesel and jet fuel from flowing to the U.S. East Coast from the Gulf Coast. Both leaders described their first summit in a lakeside Swiss villa as professional, rather than friendly, and said they agreed to hold lower-level talks on cybersecurity and arms control and to send their ambassadors back to their capitals. But there was no hiding their differences on issues such as human rights, wh...