Am I allowed to redistribute MiKTeX?
The following text is an adaption of the “TeX Live licensing, copying, and redistribution” statement found here.
If you want to redistribute and/or modify MiKTeX, please see the copying conditions.
As a general statement, the MiKTeX maintainers agree (at least within the shared purpose of working on MiKTeX) with the general principles and philosophy of the free software movement.
Therefore, to the best of our knowledge, all the software in MiKTeX meet the requirements of the Free Software Foundation's definition of free software, and the Debian Free Software Guidelines. In the rare cases of conflict, we generally follow the FSF. Furthermore, the material in MiKTeX should not require nonfree software to be useful.
In short, this means that all the material in MiKTeX may be freely used, copied, modified, and/or redistributed, subject to (in many cases) the sources remaining freely available.
Of course, you must not yourself claim copyright (especially with a proprietary license) on MiKTeX just because you redistribute it. Again, see the copying conditions for more information.