The stalemate also suited the Congolese who finished top of the group ahead of Angola at the tournament for locally-based players only.
Burkina Faso ended their campaign with a 1-1 draw against Cameroon.
Congo will face Libya in the quarter-finals while Angola will play Nigeria.
Congo managed just two shots on goal with none of them on target while Angola did manage one effort on goal from their seven as both sides earned the draw that suited them.
Angola knew a draw would be enough for them to advance while for Burkina Faso to progress they had to beat Cameroon and hope the Angolans lost to have any chance.
Burkina Faso took the lead just before half-time when Wend-Panga Bambara’s cross was parried on the ground by the Cameroon keeper Derick Fru Anye leaving Mohamed Sydney Sylla with the simplest of tasks to tap home.
Cameroon, coached by former Liverpool defender Rigobert Song, were desperate for their first goal and point of the tournament having lost their opening two games 1-0 with both goals from the penalty spot.
Their goal came from the same right-hand flank on 52 minutes as Bille Ngoundo crossed to find Patrick Moukoko at the far post to steer the ball home.
Morocco v Namibia (16:30 GMT in Casablanca)
Zambia v Sudan (19:30 GMT in Marrakech)
Nigeria v Angola (16:30 GMT in Tangier)
Congo v Libya (19:30 GMT in Agadir)