This paper presents a novel intrusion detection approach and a new infrastructure to enforce the security policy within a distributed system. The solution guaranties the consistency of the security policy and prevents any accidental or malicious update (of the local policies). The control is carried out locally (in each host) in accordance with a meta-policy that enables a distributed control to update a global security policy while satisfying global security properties. The solution is more robust in terms of fault-tolerance and resists to denial of service attacks since the solutions carries out all the control locally. Two levels of intrusion detection are proposed to guaranty the integrity and the consistency of the distributed policy. The first level (meta-level, or administration level) guarantees that each local policy evolves according to the global security properties. This level detects attacks trying inadequate alterations of the local security policies. The second level corresponds to a classical intrusion detection system. But, it can take advantages of the local policy to detect attacks that violate the security objectives. That second level enables to integrate and to adjust various classical IDS. Our approach enforces the security of large scale systems.
