The Do’s and Don’ts of Cybersecurity for Internet-Exposed Servers

Introduction to the Do’s and Don’ts of Cybersecurity

With the increasing reliance on internet-connected infrastructure, securing servers exposed to the internet is a critical task. Cyber threats such as unauthorized access, data breaches, ransomware, and denial-of-service (DoS) attacks constantly evolve, requiring administrators to implement stringent security measures. This article outlines the essential “Do”s and “Don’t”s for securing publicly accessible servers, along with best practices and references for further reading.

The “Do”s of Cybersecurity

1. Use Strong Authentication Mechanisms

• Implement multi-factor authentication (MFA) to enhance security.
• Use SSH key authentication instead of passwords.
• Ensure password policies enforce complexity and expiration.

Reference: NIST Password Guidelines

2. Keep Software and Operating Systems Updated

• Regularly apply security patches and updates.
• Automate updates where possible using package managers or Ansible.
• Subscribe to vendor security advisories for timely notifications.

Reference: US-CERT Security Bulletins

3. Enable and Configure Firewalls

• Use iptables, nftables, or ufw to allow only necessary traffic.
• Restrict SSH access to known IP addresses.
• Implement rate limiting to prevent brute-force attacks.

Reference: Guide to Linux Firewalls

4. Monitor Server Activity and Logs

• Use a log monitoring tool such as Fail2ban, OSSEC, or Wazuh.
• Centralize logging with ELK (Elasticsearch, Logstash, Kibana) or Splunk.
• Set up alerts for suspicious activities like repeated failed logins.

Reference: Security Logging Best Practices

5. Secure Remote Access

• Use a VPN or a bastion host to restrict direct SSH access.
• Change the default SSH port to reduce bot scanning.
• Implement Just-in-Time (JIT) access for privileged accounts.

Reference: Securing SSH Best Practices

6. Implement Least Privilege Access Control

• Use role-based access control (RBAC) and the principle of least privilege.
• Avoid running applications as root.
• Regularly audit user accounts and permissions.

Reference: CISA Least Privilege Guide

7. Encrypt Data in Transit and at Rest

• Use TLS/SSL certificates for HTTPS communication.
• Encrypt sensitive data using tools like LUKS or AES-based solutions.
• Ensure secure key management and storage.

Reference: OWASP Transport Layer Security

8. Use Web Application Firewalls (WAFs)

• Protect web applications from OWASP Top 10 vulnerabilities.
• Deploy open-source solutions like ModSecurity or commercial services like Cloudflare.
• Configure strict rules to prevent SQL injection and XSS attacks.

Reference: OWASP Web Application Security

The “Don’t”s of Cybersecurity

1. Don’t Use Default Credentials

• Change all default usernames and passwords immediately after setup.
• Regularly rotate credentials for sensitive services.

Reference: CVE Database for Default Credentials

2. Don’t Expose Unnecessary Services

• Disable unused ports and services (e.g., Telnet, FTP, RDP, SNMP).
• Use tools like nmap or netstat to audit open ports.

Reference: Commonly Exploited Services

3. Don’t Allow Direct Database Access from the Internet

• Restrict MySQL, PostgreSQL, and MongoDB to internal networks.
• Use application-layer authentication and encryption.

Reference: Database Security Best Practices

4. Don’t Ignore Security Alerts and Updates

• Subscribe to security mailing lists for your OS and applications.
• Regularly review vulnerability reports.

Reference: Security Mailing Lists

5. Don’t Run Applications with Excessive Privileges

• Use unprivileged user accounts for application services.
• Implement security policies like SELinux or AppArmor.

Reference: SELinux Security Guide

6. Don’t Forget About DDoS Protection

• Deploy rate limiting and IP reputation blocking.
• Use a CDN with built-in DDoS protection (e.g., Cloudflare, Akamai).

Reference: Cloudflare DDoS Protection Guide

7. Don’t Overlook Backup and Disaster Recovery

• Regularly back up critical data and test recovery procedures.
• Use immutable and offsite backups to prevent ransomware impact.

Reference: Backup Strategy Guide

Best Practices for Securing Internet-Exposed Servers

1. Conduct Regular Security Audits – Use automated tools like Lynis or OpenVAS.
2. Implement Network Segmentation – Isolate critical services from public-facing applications.
3. Use IDS/IPS Solutions – Deploy Suricata or Snort to detect and prevent intrusions.
4. Perform Regular Penetration Testing – Simulate attacks to uncover weaknesses.
5. Educate and Train Staff – Conduct cybersecurity awareness programs.

Conclusion of the Do’s and Don’ts of Cybersecurity

Securing a server exposed to the internet requires continuous vigilance and adherence to best practices. By following the “Do”s—such as enabling firewalls, enforcing strong authentication, and keeping software updated—and avoiding the “Don’t”s—such as using default credentials or exposing unnecessary services—administrators can significantly reduce security risks. Implementing these security measures proactively will help safeguard critical infrastructure from evolving cyber threats.

For further reading, consider exploring cybersecurity frameworks like NIST Cybersecurity Framework and CIS Controls, or just learn more about Basic Security.