Just found out a bug if you are using a shared computer accessing ATO email(PDF) via myGOV, even when you log out from myGOV, your ATO session is still valid thus allowing subsequent person gaining full access to your ATO account.
This bug only happen when you READ ATO email attachment directly from myGOV INBOX.
In the mean time, try avoid using a shared computer, especially in the library, workplace, university, school etc…until myGOV responded and get it fixed. Now my wife knows how much I earn :-(
Further details here
https://twitter.com/geekyjp/status/665813655997382656
Sarcasm on the Internet, right?