The subject of this article originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.
The Morgul Attack Troll was a breed of Olog-hai and unlike the Mordor breed, these Lack size, strength and armor. During the Siege of Minas Tirith, these were the first troops to attack the insides of the city once the wolfs head Grond had smashed the door open. Some of them had a little armor, but not as much as the Mordor breed.
These trolls weren't at all as strong as the ones at the black gate and were very weak to incoming arrows and spears. They cannot be mistaken with the Mountain-trolls who are nearby during the same siege.