based on ILs, as well as for defining the boundary for window messages via User Interface Privilege Isolation. Named objects, including files, registry keys or other processes and threads, have an entry in the ACL governing access to them that defines the minimum IL of the process that can use the object. MIC enforces that a process can write to or delete an object only when its IL is equal to or higher than the object’s IL. Furthermore, to prevent access to sensitive data in memory, processes can’t open processes with a higher IL for read access. FreeBSD supports Mandatory Access Control, implemented as part of the TrustedBSD project. It was introduced in FreeBSD 5.0. Since FreeBSD 7.2, MAC support is enabled by default. The framework is extensible; various MAC modules implement policies such as Biba and multilevel security. Sun's Trusted Solaris uses a mandatory and system-enforced access control mechanism (MAC), where clearances and labels are used to enforce a security policy. However note that the capability to manage labels does not imply the kernel strength to operate in multilevel security mode. Access to the labels and control mechanisms are not robustly protected from corruption in protected domain maintained by a kernel. The applications a user runs are combined with the security label at which the user works in the session. Access to information, programs and devices are only weakly controlled. Apple's Mac OS X MAC framework is an implementation of the TrustedBSD MAC framework. A limited high-level sandboxing interface is provided by the command-line function sandbox_init. See the sandbox_init manual page for documentation. Oracle Label Security is an implementation of mandatory access control in the Oracle DBMS. SE-PostgreSQL is a work in progress as of 2008-01-27, providing integration into SE-Linux. It aims for integration into version 8.4, together with row-level restrictions. Trusted RUBIX is a mandatory access control enforcing DBMS that fully integrates with SE-Linux to restrict access to all database objects. Astra Linux OS developed for Russian Army has its own mandatory access control. Smack (Simplified Mandatory Access Control Kernel) is a Linux kernel security module that protects data and process interaction from malicious manipulation using a set of custom mandatory access control rules, with simplicity as its main design goal. It has been officially merged since the Linux 2.6.25 release. ZeroMAC written by Peter Gabor Gyulay is a Linux LSM kernel patch. See also Bell–LaPadula model Access-control