You shouldn't have much problem making your flight. Its possible you could have a very short walk to the security checkpoint or a very long one, just depends on which gate you come into. Security is pretty quick and easy once you get there, however at some times of the day the lines tend to get a bit long. I wouldn't be too concerned about making your flight but you won't likely have any time to stop and enjoy the shopping at ICN and they will likely have started boarding by the time you get there so if the flight is full overhead space may be limited.