NGINX Security Hardening & Vulnerability Remediation Analysis of critical CVEs (CVE-2021-23017, HTTP/2 DoS flaws) in outdated NGINX versions, with actionable steps for mitigation: upgrades, HTTP/2 hardening, and patch automation. Includes Nessus scan validation and proactive monitoring strategies.
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Vulnerability Management Report
Prepared for: CyberTech Solutions
Prepared by: Victoria Simon
Date: April 10, 2024
1. Executive Summary
This report details the findings from a comprehensive vulnerability assessment conducted on CyberTech Solutions' Linux infrastructure and web applications using Nessus. The assessment included:
Credentialed scans of Linux servers
Web application vulnerability scans
Automated reporting configuration
Patch management via Ansible
Key findings include critical vulnerabilities in Nginx and outdated OpenSSH versions. Immediate patching and security hardening recommendations are provided.
2. Lab Objectives
Perform credentialed vulnerability scans on Linux systems.
Identify and analyze web application vulnerabilities.
Configured Nessus with SSH credentials (username: root, password: kali).
Enabled privilege escalation via su.
Scan Results:
scanned ssh vulnerability score
RECOMMENDATIONS
Following the credentialed scan and vulnerability assessment on the Linux server and hosted
applications, the following remediation steps are recommended to improve the organization’s
security posture:
System and Software Patching:
• Upgrade OpenSSH to the latest secure version to address known vulnerabilities.
• Apply the latest Linux kernel patches, including urgent updates such as CVE-2022-0185.
• Upgrade Node.js to version 18.20.1 or later to mitigate risks like request smuggling, insecure randomness, and memory management vulnerabilities (e.g., CVE-2024-27980, CVE-2024-21891, CVE-2024-21892).
• Enable automatic patch updates or integrate with a centralized patch management system to ensure timely application of security fixes.
SSH Service Hardening
• Disable weak SSH algorithms, ciphers (e.g., CBC, Arcfour), and MACs.
• Enforce key-based authentication and disable password login where possible.
• Configure custom SSH port and restrict SSH access using firewall rules or TCP wrappers.
• Limit access to specific IPs and implement two-factor authentication (2FA) for remote connections.
User and Access Control
• Disable root login via SSH; use sudo for privilege elevation.
• Remove unused or legacy user accounts and enforce strong password policies.
• Set up account lockout mechanisms to prevent brute-force attacks.
• Audit user groups and privileges to ensure least privilege is enforced.
Host and Network Hardening
• Disable unnecessary services and close unused ports.
• Use hardening tools like Lynis, OpenSCAP, or CIS Benchmarks to enforce best practices.
• Implement firewall rules to limit network exposure and prevent lateral movement.
Monitoring, Logging, and Detection
• Enable detailed logging for SSH, sudo, and system events.
• Integrate logs with a SIEM platform for real-time monitoring and alerting.
• Monitor for suspicious behavior and anomalous access patterns.
Application and Dependency Security
• Run npm audit or yarn audit to scan and fix Node.js dependencies.
• Regularly test applications with dynamic and static analysis tools (DAST/SAST).
• Use a Web Application Firewall (WAF) to block known web-based attacks.
Backup and Recovery
• Schedule regular backups of configurations and critical data.
• Test disaster recovery and backup restoration procedures periodically.
Security Awareness and Governance
• Conduct regular security training for system administrators and developers.
• Maintain updated security policies, procedures, and asset documentation.
• Perform periodic vulnerability assessments and penetration tests to stay proactive.
Task 2: Web Application Scan
Nginx Vulnerabilities:
CVE-2021-23017 (CVSS 7.5): Buffer overflow in Nginx 1.15.5.
Post-Remediation: Document changes and update incident response plans to include HTTP/2/NGINX exploit scenarios.
7. Challenges and Solutions
Challenge
Solution
nessus plugins installation
I could not increase my ram, so i had to wait for longer hours to install the plugins after so many hours and failed attempts
SMTP email failures
Generated Gmail app password
Ansible playbook errors
Verified YAML syntax with ansible-lint
8. Conclusion
The assessment identified critical vulnerabilities in CyberTech’s web infrastructure due to outdated NGINX versions and unpatched CVEs, exposing the organization to DoS attacks, memory corruption, and information disclosure. To address these risks, immediate upgrades, HTTP/2 hardening, and automated patch management are essential.
A follow-up scan should be conducted post-remediation to validate fixes. Sustaining a proactive security posture through regular updates and monitoring will help mitigate future threats and ensure long-term resilience.
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