One of the biggest possible security leaks, both for private individuals and companies, lies in not being thorough about removing data from old hard disks. When data is not wiped or securely deleted from a given hard disk, it becomes possible (if not always easy) for people to attempt and recover the data. For innocuous data such as mundane documents and other such files, this possibility may not seem like much of a risk.
However, for hard disks handling confidential information such as financial matters, personal information, and the like, this becomes a serious issue. It has been shown that most people and organizations are not careful about their information that is left on old hard disks. On a survey of a typical sample of old or recycled hard disks, it is more than likely that one would be able to recover some personal information, or even confidential information on a larger scale. These include company employee information, financial transaction information, and so on.
This happens because ordinary file deletion or disk reformatting is not enough to dissuade a determined hacker from recovering data. Normal deletion does not actually remove the file data...