Obamacare Site Subject To Unsuccessful Cyber Attack: Official

WASHINGTON, Nov 13 (Reuters) - The Obama administration's troubled HealthCare.gov site has been subject to an unsuccessful cyber attack aimed at overwhelming and taking down the site, a U.S. cybersecurity official said on Wednesday.

"We are aware of one open source action attempting a denial of service attack that has been unsuccessful," Roberta Stempfley, acting assistant secretary of the Department of Homeland Security's Office of Cybersecurity and Communications, told lawmakers.

Testifying at the House of Representatives Homeland Security Committee, Stempfley also said the DHS was aware of "about 16" reports from the Department of Health and Human Services on investigations related to the site's security.

It was unclear from the testimony whether the reports were related to actual cyber attacks, threats of attacks or other operational problems.

Stempfley said the Centers for Medicare and Medicaid Services, the lead health agency managing the rollout of the site, had not sent a specific request for help, so federal cyber officials had not been providing any technical assistance. (Reporting by Alina Selyukh; Editing by David Brunnstrom)