Attorney Ty Cobb said McCarthy "did not have access to the information she is accused of leaking," The Washington Post reported Tuesday.
The Post won a Pulitzer Prize for its reporting on eastern European detention centers it attributed to current and former government officials on three continents.
"She categorically denies leaking classified information," Cobb told The New York Times.
While reports had said the inspector general's office employee was fired last week because of the secret-prisons leak, CIA officials told CNN and The Times McCarthy was fired for a "pattern" of conduct -- not a single leak.
CIA Director Porter Goss in January ordered McCarthy and others to undergo polygraph tests, The Times and CNN reported.
The Justice Department is investigating that case as well as leaks to The Times, which won a Pulitzer for its reporting about the National Security Agency's warrantless domestic spying program, CNN reported.