Security reviews and compliance audits are crucial processes to ensure adherence to international standards such as PCI-DSS (Payment Card Industry Data Security Standard) and ISO 27001 (Information Security Management System). These standards define requirements for security measures to protect sensitive data and information systems. In this article, we will focus on how to conduct these processes on the CentOS 7 operating system, a popular Linux distribution used in many enterprise environments.

Basic Principles

Before initiating reviews and audits, it's essential to understand the fundamental principles behind these processes:

• Scope Identification: Determine which systems and data fall under the requirements of the standard.
• Risk Assessment: Identify and evaluate potential security threats and vulnerabilities.
• Risk Mitigation Measures: Implement security measures and procedures to mitigate identified risks.
• Documentation and Monitoring: Record all processes and measures, maintain audit logs, and regularly review them.

Regular Security Reviews

1. Patching and Updating

• Regularly update the system and applications to the latest versions using the yum update and yum upgrade commands.
• Check for available security patches and apply them without delay.

2. User Account Management

• Review all user accounts on the system using commands such as cat /etc/passwd and getent group.
• Ensure each account has a clearly defined purpose, and deactivate those no longer needed.

3. Securing Network Services

• Use commands like netstat -tuln or ss -tuln to identify running network services.
• Restrict access to network services only to necessary ones and utilize a firewall such as firewalld or iptables for access control.

4. Data Security

• Encrypt sensitive data stored on disk and transmitted data using tools like LUKS for disk encryption or SSL/TLS for network transmission encryption.
• Implement regular backups and secure the backups.

Compliance Auditing

1. Automated Tools

• Utilize tools like OpenSCAP, which provides a framework for scanning and assessing security based on predefined profiles for various standards.
• Use aide or tripwire for file integrity checking.

2. Configuration Review

• Conduct reviews of system and application configurations following recommended practices for the respective standard.
• Review configuration files such as /etc/ssh/sshd_config, /etc/sysctl.conf, and others for strictness and security settings.

3. Logging and Monitoring

• Configure syslog or other logging services to record important events.
• Regularly analyze logs for suspicious activity or potential security incidents.

4. Physical and Operational Security

• Don't overlook physical server and device security.
• Establish and maintain processes for change management, incident management, and disaster recovery.

 

Performing regular security reviews and compliance audits on CentOS 7 requires a thorough approach and constant attention. By implementing the steps outlined above and leveraging automated tools, you can ensure your system aligns with PCI-DSS and ISO 27001 standards. Regular review of these processes and updating them in response to new threats and changes in standards is also crucial.