Despite piling on late pressure, the home side failed to create sufficient clear cut chances and Jordan Robertson might have sneaked all three points for Iron in injury time with a curler which flew just wide at the far post.
Scunthorpe only troubled Adam Collin in the Carlisle goal sporadically in a stop-start first half, although Jimmy Ryan spelt early danger with a rasping cross shot which flew just wide of the far post.
Carlisle had the better of the possession and Lee Miller - who spent time on loan at Glanford Park last season - was just off target with a diving header before Liam Noble beat the diving Sam Slocombe with a raking low drive which skidded a fraction wide of the left hand post.
When a chance did fall to the Iron straight after the break, captain Cliff Byrne failed to take advantage. The Irish defender found space in the box but sliced his shot against the legs of a defender.
Carlisle, looking lifeless in attack, did not delay making changes, with Jordan Cook and Andy Welsh coming on up front with 25 minutes remaining.
The Cumbrians suffered a blow when they lost leading scorer Miller through injury.
Lubo Michalik almost grabbed a late goal for the home side, only to see his thunderous shot bravely blocked by former Carlisle defender Paul Reid.