You would not believe what has been recovered from dumpsters from professional security teams who, while performing a test of a company’s security, dug through the trash.
Trash from banks and health care facilities in particular provide a plethora of sensitive information that hackers look for. Names, addresses, phone numbers, social security numbers, and financial information are the most obvious targets, but what are some of the less obvious? Old software disks from system updates tell the hacker what software you are using. A bill from your utilities or even your computer support company can give away vital information to a hacker who is willing to disguise himself to gain physical access to your building. Though most hackers will not want to risk physical entry to your system, trash recovered from security tests have provided everything from administrator level passwords to layouts of your internal network.
Also, physical machines discarded often offer a wealth of information. The most obvious is hard drives left intact inside the machines. But, also, the outside of the system can provide information too. You have corporate asset tags that tell exactly what company owned the machine. Corporate Network ID tags sometimes have the network name and internal IP Address listed, this information could also be used. Some people even tape passwords to machines and monitors.
Just a side note, many large companies use network ID tags. Great idea, but could you make them smaller, or place them on the back or bottom of the machines? Or, just limit the information on them. They stick out like a sore thumb to any visitor walking through the building.