/usr/lib/x86_64-linux-gnu/libcppunit.so is in libcppunit-dev 1.13.1-2ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcppunit-1.13.so.0.0.1
/usr/lib/x86_64-linux-gnu/libcppunit-1.13.so.0.0.1