The information, which includes details of undercover operatives and 'secret' CIA facilities, can be purchased using internet services that search publicly available government information.
The Chicago Tribune claims to have uncovered more than 2,600 people who work for the CIA, and said that the security agency had confirmed that part of the list included details on covert agents.
This list included the names of CIA operatives assigned to US embassies throughout Europe. At the CIA's request the Chicago Tribune has not published this information.
The internet searches also identified CIA properties in Florida, Chicago, Ohio, northern Virginia, Pennsylvania, Utah and Washington state.
Some of the buildings are official premises under guard, while other addresses appear to be private residences.
"Cover is a complex issue that is more complex in the internet age," said Jennifer Dyck, a chief CIA spokeswoman. "There are things that worked previously that no longer work."
Dyck refused to comment on the actions that would be taken to remedy the security breach "since we don't want the bad guys to know what we're fixing".
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