| Mandatory Access Control |
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In Computer Security , mandatory access control ('''MAC''') is a kind of Access Control defined by the Trusted Computer System Evaluation Criteria
Authorization is contingent on a formalized process that documents prerequisite trust in the individual gaining access. An example of a such a document is a security clearance letter of consent. An example of such a process is a security clearance background check mandated by Executive Order 12958 . {Link without Title} MAC's most important feature involves denying User s full control over the access to resources that they create. The system security policy (as set by the administrator) entirely determines the access rights granted, and a user may not grant less restrictive access to their resources than the administrator specifies. ( Discretionary Access Control systems permit users to entirely determine the access granted to their resources, which means that they can (through accident or malice) give access to unauthorised users.) For MAC, the access control decision is contingent on verifying the compatibility of the security properties of the data and the clearance properties of the individual (or the process proxying for the individual). The decision depends on the integrity of the metadata that defines the security properties of the data, as well as the security clearance of the individual or process requesting access. Security mechanisms that protect such metadata and the access control decision logic from corruption are MAC-critical objects and require appropriate robustness. MAC is most commonly applicable to Classified National Security Information where best effort mechanisms are inadequate; absolute enforcement is mandated. If individuals or processes exist in the system environment that may be denied access to any of the data in the system environment, then the system must be trusted to enforce MAC. This implies varying degrees of robustness in the system. For example, more robustness is indicated for system environments containing classified Top Secret information and uncleared users than for one with Secret information and users cleared to at least Confidential. To promote consistency and eliminate subjectivity in degrees of robustness, an extensive scientific analysis and risk assessment of the topic produced a landmark benchmark standardization quantifying security robustness capabilities of systems and mapping them to the degrees of trust warranted for various security environments. The result was documented in CSC-STD-004-85. {Link without Title} Two relatively independent components of robustness were defined: Assurance Level and Functionality. Both were specified with a degree of precision that warranted significant confidence in certifications based on this criteria. The level C2 (not a MAC capable category) was fairly faithfully preserved in the Common Criteria, as the [Controlled Access Protection Profile (CAPP) [http://www.commoncriteriaportal.org/public/files/ppfiles/capp.pdf]. MLS Protection Profiles (such as MLSOSPP similar to B2) [http://www.commoncriteriaportal.org/public/files/ppfiles/PP_MLOSPP-MR_V1.22.pdf] is more general than B2. They are pursuant to MLS, but lack the detailed implementation requirements of their Orange Book predecessors, focusing more on objectives. This gives certifiers more subjective flexibility in deciding whether the evaluated product’s technical features adequately achieve the objective, potentially eroding consistency of evaluated products and making it easier to attain certification for less trustworthy products. For these reasons, the importance of the technical details of the Protection Profile is critical to determining the suitability of a product. Such an architecture prevents an authenticated user or process at a specific classification or trust-level from accessing information, processes, or devices in a different level. This provides a containment mechanism of users and processes, both known and unknown (an unknown program (for example) might comprise an untrusted application where the system should monitor and/or control accesses to devices and files). IMPLEMENTATIONS
ARCHITECTURES Several Security-focused Operating Systems implement MAC, and it forms a core part of the FLASK operating systems. The FLASK and Generalized Framework For Access Control (GFAC) architectures, coupled with MAC, become enabling technologies of Multilevel Security systems. SEE ALSO
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