/usr/lib/libCOSDynamic4.so.1 is in libcos4-1 4.1.6-2.1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libCOSDynamic4.so.1.6
/usr/lib/libCOSDynamic4.so.1.6