The Russian club, which has qualified for the last 16 of the Champions League after finishing second in Group B, was also fined 25,000 euros for the violation by UEFA's disciplinary committee.
European football's governing body added that the pair had already served the suspension, as they missed last week's Champions League match against Besiktas when they were provisionally banned pending the disciplinary hearing.
CSKA said earlier this month that the players had been the victims of a procedural error by the club's medical staff.
"Our medical staff had made a technical error, failing to disclose cold medicine Sudafed during a doping test on November 3 in Manchester," said the club.
The club said the drug taken by Ignashevich and Berezutsky had not been on a banned list but still needed to be disclosed.
CSKA drew the match 3-3. They went on to win their last two games, at home to VfL Wolfsburg and away to Besiktas to finish second with 10 points, three behind Manchester United, and qualify at the expense of the Bundesliga champions.
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