/usr/lib/x86_64-linux-gnu/libILUT.so.1 is in libdevil1c2 1.7.8-7ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libILUT.so.1.1.0
/usr/lib/x86_64-linux-gnu/libILUT.so.1.1.0