[raxxorraxor]

Often it isn't you that is leaking data but one of your suppliers or customers which also have contact info of your employees. If you have many suppliers and customers, you can be sure that the names, positions and contact information of your employees is available to hostile third parties at some point.

It could also be a data from a broker because those do sell such data as well and online services sadly do not care too much for privacy.

We often get spam where attackers even faked our mail signatures (the one you put at the end of your mail, not the signature to verify your domain).

"That cannot be a real mail from the boss, he would never be that friendly"