Firefox and Mozilla can associate a cookie with multiple domains when the DNS resolver has a non-root domain in its search list, which allows remote attackers to trick a user into accepting a cookie for a hostname formed via search-list expansion of the hostname entered by the user, or steal a cookie for an expanded hostname, as demonstrated by an attacker who operates an ap1.com Internet web site to steal cookies associated with an ap1.com.example.com intranet web site.