Using AGPL v3 software in an enterprise deployment

Question

An enterprise utilizes the source code of a network software product licensed under the AGPL v3. It modifies the source code but does not share the changes with the original developer and copyright holder, and keeps the changes private. It then hosts the modified version within its servers, but does not distribute the source code as a bundle to any third parties. It allows a closed group of its authenticated customers (not the general public) to interact with this modified product - via web services - fronted through a web portal of the enterprise.

Is the enterprise violating any of the terms of the AGPL v3? If so, which exactly?

Answer 1

Term 13 of the AGPLv3:

13. Remote Network Interaction; Use with the GNU General Public License.

Notwithstanding any other provision of this License, if you modify the
Program, your modified version must prominently offer all users interacting
with it remotely through a computer network (if your version supports such
interaction) an opportunity to receive the Corresponding Source of your
version by providing access to the Corresponding Source from a network
server at no charge, through some standard or customary means of
facilitating copying of software. This Corresponding Source shall include
the Corresponding Source for any work covered by version 3 of the GNU
General Public License that is incorporated pursuant to the following
paragraph.

Those customers interacting with the software are such users, it seems to me.

It gets hairy because they don't interact directly with the services but through a portal web site; for that you need to talk with a lawyer, or ask on the OSS Stack Exchange perhaps. I'd say the license is probably intended to make it apply to that case, but I don't know if it actually does.