Hackers broke into more than a dozen Web sites for members of the U.S. House of Representatives in the past week, replacing portions of their home pages with digital graffiti, according House officials. The landing pages at house.gov for Reps. Duncan Hunter (R-Calif.), Jesse L. Jackson, Jr. (D-Ill.), and Spencer Bachus (R-Ala.) were among at least 18 member pages that were defaced in a series of break-ins that apparently began earlier this month, according to zone-h.com, a site that archives evidence of Web site attacks. Adam Bozzi, a spokesman for Rep. Harry Mitchell (D-Ariz.), confirmed that Mitchell’s site was among those hacked. Bozzi said it appears the attackers broke in by guessing passwords used to administer the site. Bozzi said the messages that the hackers left behind had been erased, and that his office now has stronger passwords for the site. The hackers replaced portions of the member pages with