Foreigners can buy private properties in Singapore.
HDB is not considered private properties.

If you are working in singapore, you can use your monthly CPF (like malaysia's EPF) to pay for mortgage, not enough, then top up cash.

This one of the reason why Properties is highly priced.

The mortgage interest rate for private properties is around 4-5%, as compared to Malaysia's 7%. For HDB, it is 2.6% if you borrow from the government (Your CPF Account).