/usr/lib/x86_64-linux-gnu/libpam.so is in libpam0g-dev 1.1.3-7ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/libpam.so.0
/lib/x86_64-linux-gnu/libpam.so.0