A man was fatally shot in a drive-by attack Friday afternoon in Grand Boulevard on the South Side.The 24-year-old was standing on a sidewalk just before 3 p.m. in the 200 block of East 43rd Street when someone in a white sedan fired shots before the driver fled, Chicago police said.The man suffered 12 gunshot wounds to his head and body. He was taken in critical condition to University of Chicago Medical Center, where he was pronounced dead, police said.No arrests were reported.