All federal departments using software vulnerable to the so-called Heartbleed bug have been ordered to immediately disable public websites.

This a precautionary measure until the “appropriate security patches are in place and tested” but did not indicate how many departments are involved.

Chief Information Officer  (Treasury Board) says that while disruptive, “this is the best course of action to protect the privacy of Canadians.”

The statement adds that until measures are applied, “Canadians will be unable to access certain Government of Canada websites.”

The Heartbleed bug is caused by a flaw in OpenSSL software, which is commonly used on the Internet to provide security and privacy.

The bug is affecting many global IT systems in both private and public sector organizations and has the potential to expose private data.

The Canada Revenue Agency had shut down its online filing services on Wednesday and said it hoped they would be up and running again by the weekend.