One of the most dangerous insider threats in a supervisory control and data acquisition (SCADA) system is deontological threat. The concept of deontological threat has been introduced to underline the operator performance when he/she does not perform his/her duties perfectly or decides to abuse the privileges in order to perform malicious operations in remote substations. In this paper, a new alarm-and-trust based access management system (ATAMS) has been proposed that is able to reinforce the security of the SCADA system against the deontological threats. In the proposed ATAMS, the accessibility of a remote substation will be determined based on the operator trust and the integrity level of the substation. The value of operator trust is calculated using the performance of the operator, periodically or when an anomaly is detected. One of the opportunities of the ATAMS is its ability in detecting the anomalies, which is rooted in the deontological threats.
