After a cagey opening half, the second livened up as Erik Huseklepp gave Birmingham the lead before defender Mark Hudson finished coolly to put Cardiff back on level terms.
The result leaves Birmingham and Cardiff both on 60 points in sixth and eighth places respectively, on the brink of the play-off places.
The home side made four changes from the team that lost to Portsmouth 4-1 in midweek, with Erik Huseklepp returning from suspension to replace Nikola Zigic and start upfront alongside Marlon King. For Cardiff, manager Malky Mackay stuck with the same XI who drew 2-2 against Coventry.
The visitors started brightly and continued to take the game to Birmingham throughout the first half but had little in the way of chances to show for it.
With 10 minutes gone, Mark Hudson should have hit the target from an inviting Peter Whittingham corner, but the defender could only head over the bar after losing his marker.
Seconds later it was the away side on the front foot again, this time Ben Turner dragging his shot wide of Boaz Myhill's left-hand post after a swift counter-attack from the Bluebirds.
Joe Mason, in charge of leading Cardiff's attack, almost got on the end of another rapid break before blasting off target when it seemed easier to test Myhill after more great play from Mackay's men.
All in all, it was a disappointing half for the hosts and, but for a long-range effort from midfielder Guirane N'Daw struck from range that was easily saved by David Marshall, the crowd had little to shout about going in at the break.
The second half started as the first, but it was the hosts who had a glorious opportunity to take the lead against the run of play when Jordon Mutch was felled inside the Cardiff box by the over-eager Andrew Taylor. Up stepped Marlon King but the striker's poor effort was well saved by Marshall.
Seconds later, Cardiff had Marshall to thank again, as this time the Scottish goalkeeper reacted quickly to deny Huseklepp in a one-on-one situation.
Then came the opener. A superb run from Chris Burke ended in the midfielder picking out Huseklepp who made no mistake in striking the ball beyond Marshall to put the hosts ahead. It was Burke's14th assist of the season.
Ten minutes later and a spirited Cardiff found their equaliser. A set-piece from Aron Gunnarsson eventually fell to Hudson who showed great composure to guide the ball low past Myhill.
Chances then became few and far between after Cardiff drew level with only a brave save from Marshall from Burke the only real highlight.