The organization reviews audit records (e.g., user activity logs) for inappropriate activities in accordance with organizational procedures. The organization investigates any unusual information system-related activities and periodically reviews changes to access authorizations. The organization reviews more frequently the activities of users with significant information system roles and responsibilities. The extent of the audit record reviews is based on the FIPS 199 impact level of the information system. For example, for low-impact systems, it is not intended that security logs be reviewed frequently for every workstation, but rather at central points such as a web proxy or email servers and when specific circumstances warrant review of other audit records. NIST Special Publication 800-92 provides guidance on computer security log management.