/lib/x86_64-linux-gnu/libcgroup.so.1 is in libcgroup1 0.41-8ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/libcgroup.so.1.0.41
/lib/x86_64-linux-gnu/libcgroup.so.1.0.41