# A Proposal for a Zero-Trust-Based Multi-Level Security Model and Its Security Controls
## 3 Introduction of MLS Classification Criteria and Proposed Zero-Trust-Based MLS Model
### Risk Analysis of Proposed Zero-Trust-Based MLS Model  
Security risk refers to the potential for malicious actors (or unintentional actions or incidents) to harm, damage, cause loss to, render unusable, or reduce the effectiveness of security controls for organisational assets [38]. This section identifies and systematically classifies various security risks that may arise within an organisation. The identified risks that could impact data or systems across all levels (C, S, and O) are defined as General risks. Risks that may occur across two levels are classified under the level associated with the higher data sensitivity.  
Tables 2-5 illustrate the risks categorised into the following four classifications: General, Classified, Sensitive, and Open.  
\begin{table}
\begin{tabular}{l l} \hline \hline \multicolumn{1}{c}{**General Risks**} & \multicolumn{1}{c}{**Description**} \\ \hline Data Tampering & Possibility of decreased reliability due to unauthorised modification of data. \\ \hline Insider Threat & Potential for insiders to leak or misuse data without authorisation. \\ \hline Unauthorized Access & Risk of unauthorised users accessing the system. \\ \hline Malware and Ransomware Infection & Potential for data loss or system failure due to malware infection. \\ \hline Privilege Abuse & Possibility of authorised users improperly accessing or modifying data. \\ \hline Poor Log Management & Limitations in detecting and tracking abnormal activities. \\ \hline Phishing and Social Engineering Attacks & Risk of users being deceived into leaking data or credentials being stolen. \\ \hline Data Backup Failure & Failure to recover data during system failures. \\ \hline Device Loss and Theft & Risk of data exposure due to device loss or theft. \\ \hline DoS and DDoS Attacks & Attacks that compromise availability through denial-of-service. \\ \hline Network Security Vulnerabilities & Risk of external attacks if network security is weak. \\ \hline Administrator Privilege Compromise & Possibility of unauthorised access to critical national data if administrator privileges are stolen. \\ \hline Lack of User Security Awareness & Potential for basic security incidents due to users’ lack of security awareness. \\ \hline \hline \end{tabular}
\end{table}
Table 2: General risks.  
\begin{table}
\begin{tabular}{l l} \hline \hline \multicolumn{1}{c}{**Potential Risks**} & \multicolumn{1}{c}{**Description**} \\ \hline National Secret Leakage & Risk of exposing classified information that could severely impact national security if leaked. \\ \hline Cyber Terrorism and Attacks & Risk of data leakage or destruction due to attacks targeting critical national assets. \\ \hline Real-Time Monitoring Failure & Potential risks arising from the failure of real-time monitoring. \\ \hline Physical Security Breach & Risk of intrusion, theft, or tampering at physical locations where data are stored. \\ \hline Encryption Key Management Failure & Risk of exposing encrypted confidential information due to compromised encryption keys. \\ \hline High-Risk System Vulnerabilities & Potential for external attacks due to system vulnerabilities. \\ \hline Lack of Regular Security Audits & Risk of security defects being exposed if periodic audits are not conducted. \\ \hline \hline \end{tabular}
\end{table}
Table 3: Risk according to the Classified level risks.