This is very worrying, an AN-26 does not have the service ceiling of what I would expect the MH flight to be travelling at. A trip seven would be about 2500m higher.
Its also smaller. However, if they identified the target and aimed the missile visually, its possible that they mistook a 777@10000m for an An-26@7500m. I doubt the rebels have much in the way of air search radar. If this was a rebel misidentification, what probably happened is that they fired the missile line-of-sight with the seeker active.
