Better yet, if your company employs H1-B visa holders, they are required by law to put up the job advertisement along with salary offered in a public area of the office.

This requirement is to give opportunity to existing employees for the new position.

In a small company of about 400 people, where I worked, the job advertisements were posted in the kitchen area and it wasn't very hard to deduce what the salary of the newly joining member of your team is.