Policies
Policies
For the general user, the delete or format command appears to be the logical method of removing unwanted data files. These methods, however, are like sweeping something under the carpet: you may not be able to see it, but it's still there. All that deletion has done is remove the pointer to the files, with the data itself residing in unallocated space on the hard drive. This means that data recovery is possible using various software tools.
When sensitive information is stored on the hard drive of a machine that is to be surplussed or transferred to another individual or department, it is therefore imperative that extra measures be taken to wipe clean the hard drive before the computer leaves your area of responsibility. This document describes some common methods and software to assist you with the sanitization process. It also includes links to articles that provide detailed technical descriptions of what occurs during this process.
The NIST Special Publication 800-88, Guidelines for Media Sanitization, provides an overview of sanitization techniques and requirements. According to the publication, the purpose of sanitization is "to render access to target data (the data subject to the sanitization technique) on the media infeasible for a given level of recovery effort", and describes the three categories of action to be taken to sanitize media as:
See Section 5 of the document for a more detailed summary of sanitization techniques, and Appendix A for sanitization requirements for specific media/device types.
The three most common techniques for properly sanitizing hard drives are:
Note that when removing sensitive information, don't forget storage devices such as thumb drives, back-up external hard drives and CDs. Also, be sure to erase any stored names and numbers from phones and fax machines.
EXTRA: OIT has a hard drive crusher used for crushing no-longer needed drives containing data covered under the Brown Restricted Information Policy. Contact the IT Service Center for more details and to arrange an appointment.
The following chart is a collection of disk wiping software recommended by departmental computing coordinators (DCCs) or listed on a variety of other University and security sites. The inclusion of any title does not indicate an endorsement by Brown University or the Office of Information Technology, and has only been provided as an aide in making a decision that best matches your specific needs. See also the Wikipedia list of data-erasing software.
Program | Cost | Platform | Comments |
---|---|---|---|
Darik's Boot and Nuke (DBAN) |
Shareware | Windows & Mac | Self-contained boot disk that securely wipes the hard disks of most computers; consumer-grade, appropriate for bulk or emergency data destruction. (Acquired by Blancco in 2012.) |
Disk Utility | Free | Mac OS X | Securely erases data as well as disk’s empty space (latter prevents the recovery of erased files without erasing the entire disk). |
Disk Wipe | Shareware | Windows | Permanently wipes sensitive data on partitions and disk volumes. |
East-Tec DisposeSecure | $29.95 | OS independent | Erase computer hard drives, partitions or media devices; US DOD compliant. |
Eraser | Shareware | Windows | Completely removes sensitive data from a hard drive by overwriting it several times with carefully selected patterns. |
KillDisk (Active@KillDisk) | Free version, Pro versions start at $39.95 | Windows, Linux | Powerful and compact software allowing you to destroy all data on hard disks, SSD and USB drives completely, excluding any possibility of future recovery of deleted files and folders; a hard drive and partition eraser utility. |
Linux | Free | Linux | Use built-in dd, wipe and shred tools |
Paragon Disk Wiper Professional |
$39.95 | Windows | Disk Wiper Pro meets DoD sanitizing standards; includes 10 different disk sanitization methods |
sDelete | Free | Windows |
A command line utility that allows you to delete one or more files and/or directories, or to cleanse the free space on a logical disk; DoD-compliant secure delete program. |
secure rm | Shareware | Unix & Windows command line program | Secure file removal utility for Unix and Unix-like computer systems; command-line compatible rm overwrites file contents |
ShredIt | Free trial, $24.95 | Windows, Mac, iOS, Android | Easy interface, configurable overwrite pattern and number of overwrites |
Wipe | Shareware | Linux, Unix | Uses Gutmann's erase patterns, erasing single files and accompanying metadata or entire disks |
WipeDrive (Home version) | $29.95 | Windows, Intel-based Macs, Linux | Securely erases all hard drive or external storage information; military grade; wipe up to 3 different hard drives |
WipeDrive (Enterprise version) | Contact vendor for details (licensed per client) | Windows, Intel-based Macs, Linux | Flexible licensing permits wiping desktops, laptops, networked computers, servers, individual drives, or RAID arrays with one product and one block of licenses. Erase hard drives remotely. |
Each of the software products listed above comes with specific instructions, some with an easy-to-use wizard interface. KillDisk (recommended by some DCCs) is the software of choice at Northern Illinois University. Their support for this product includes detailed instructions on its use. Dell offers an overview document How Do I Erase Data from My Hard Drive?.
In addition to the software offered above, Mac computer hard drives can be cleared by zeroing their data. Note that zeroing data (aka "low level" format) may take a long time and depends on the hard disk size. It is recommended to use the "8-way random" feature in conjunction with the "zero all data" option. See the section "Securely erase a disk" in the article Disk Utility 12.x: Erase a Disk, CD or DVD for details.
Last Reviewed: March, 2016