Unable to find stud in shared wall
Mounting the cabinets in this situation may well be a non-trivial construction project due to the lack of studs and the wall serving as fire separation between dwellings under the control of different occupants.

There are two ways to determine the construction in this case.


Locate accurate architectural plans depicting the original construction. Such plans may not be readily available.
Destructive investigation entailing opening the wall up and looking to see how it is built.


Irrespective of the method used to determine construction, the mounting of cabinets in the absence of studs requires an appropriate plan suitable for the actual construction. Whether such a plan will require a detailed design so that the cabinets are self supporting depends, of course, on the nature of the existing construction.

Alternatively to cabinets, furniture might by used to meet the functional requirements of the larger project.