State attorneys general told five of the nation’s largest banks on Tuesday they face a potential liability of at least $17 billion in civil lawsuits if a settlement isn’t reached to address improper foreclosure practices, according to people familiar with the matter. The figure doesn’t cover additional billions of dollars in potential claims from federal agencies such as the Department of Housing and Urban Development and the Justice Department. State and federal officials haven’t proposed a specific comprehensive settlement figure, but Tuesday’s discussions represented the first effort to formally quantify potential liability.