Organizations that provide any public computer access or kiosks should acquire and implement Reboot to Restore software to return publicly accessible devices to a clean baseline state after each use.
Control Type: Technical
Control Function: Preventive
Some organizations deploy desktop workstations for use by many users on an inconsistent basis. These systems are usually for general tasks like web browsing, word processing, and email. There is no expectation that any user has any claim of ownership over any device, or that data will be preserved for future use. Examples of this deployment scenario include school computer labs, hotel kiosks, and public library workstations.
A great number of risks come with such a scenario. Workstations that are fully open to the public run into issues with accountability, since many of them utilize generic autologin or kiosk accounts. This strategy is generally not recommended, and such organizations should seek ways to digitally identify the individuals accessing the devices so that an audit trail can be kept. One of the more concerning risks associated with public use devices is the risk of malware infection by an adversary who takes advantage of the service. The adversary could bring in an infected flash drive, install a keylogger, or intentionally install a trojan horse. Unintentional negative effects can also arise, such as younger or older users installing adware programs, PUPs, or malicious browser extensions. If the device is left in this state user-to-user, then anyone who uses the device after the adversary runs the risk of having their data and digital integrity compromised. This is unacceptable for any organization.
A specific category of software called Reboot to Restore exists to address this exact issue. This software runs at a deep level on a system and essentially redirects any modifications from a permanent state to a temporary state. This encompasses file downloads, system registry edits, and newly installed programs. When the system is rebooted, the temporary changes are discarded, and the system is restored to its fresh baseline state. Organizations can deploy policies via Group Policy or MDM templates to make “Restart” the only option for power settings, basically forcing users to initiate the restore process after they are finished using the system.
A classic reboot to restore program is Deep Freeze by Faronics, which works with both Windows and macOS. This has been a mainstream option for reboot to restore for decades now. Horizon DataSys Reboot Restore offers both standard and professional versions of their software implementation. For organizations that are budget constrained, the built in Windows Unified Write Filter (UWF) can provide similar services without needing to purchase third party software. Regardless of what reboot to restore software is chosen, organizations should never assume that the program will eliminate any possibility of compromise, since this is not possible. A level of inherent risk will always be present when providing publicly accessible workstation access.