Trusted software, whether securely developed in house or obtained from a trusted source, should have baseline data integrity established when first created or obtained, such as by using hash algorithms to obtain a hash value that would be used to validate the source prior to use of the software in a given system. Hardware in the repository should be stored in boxes or containers with tamper-evident seals. Hashes and seals should be checked on a regular basis employing the principle of separation of duties.

Example

You are the primary system build technician at a medium-sized company. You have been put in charge of creating, documenting, and implementing a baseline configuration for all user systems [c]. You have identified a minimum set of software that is needed by all employees to complete their work (e.g., office automation software). You acquire trusted versions of the software and build one or more baselines of all system software, firmware, and applications required by the organization. The gold version of each baseline is stored in a secure configuration management system repository and updated as required to maintain integrity and security. Access to the build repository for updates and use is carefully controlled using access control mechanisms that limit access to you and your staff. All interations with the repository are logged. Using an automated build tool, your team builds each organizational system using the standard baseline

Potential Assessment Considerations

• Does an authoritative source and repository exist to provide a trusted source and accountability for approved and implemented system components [c,d]?