The disclosure came after weeks of pressure from journalists.
An official emphasized the phishing scam is "not something internal to our system."
House Republicans will call up legislation next week that forces Democrats to choose between funding research for pediatric diseases or continuing the taxpayer funding of political party conventions.
Republicans say officials knew ObamaCare "was not ready for prime time.”
The FBI charged 49 current and former Russian diplomats with defrauding Medicaid.
An official characterized the error rate on forms as a substantial improvement from October.
States declining to participate in Medicaid expansion will lose billions in federal funds.
That's only a slight uptick, however, from mid-October.
The House could consider legislation related to Medicare's flawed physician payment formula next week, although it is unclear whether the chamber will weigh a permanent or a short-term "doc fix." House Majority Leader Eric Cantor (R-Va.) announced that the chamber could hold a vote pertaining to Medicare's sustainable growth rate (SGR) in the final work week before the holiday recess.
Physicians who accept Medicare payments are facing a pay cut of about 25 percent on Dec. 31, when the current fix is set to expire, putting pressure on Congress to act before next year. There are signs that lawmakers could move forward on a permanent fix this month, though final passage appears unlikely as lawmakers rush to finish other work. Elise Viebeck at The Hill reports.
Rep. George Holding (R-N.C.) has proposed legislation that would require federal officials and others who use ObamaCare data to commit identify theft to serve a five-year prison term.