This is part of the Operation Broken Eagle DLC.
There are only 29 cameras placed throughout the game that you will need to hack. These cameras are identical to the ones in the main campaign, however in order to hack these particular ones you will need to walk up to the base of the camera tower. They will be indicated by yellow circles on your map, and they only appear on your map when you are close to them.
Note: All of these achievements in this DLC need to be completed prior to going to the Mayor's Mansion. After that point, you will not be able to obtain these achievements and you will be required to start a new campaign to do so.