TCP port 11211 is the default port used by the Memcached caching system, which is commonly used to speed up dynamic web applications by caching frequently accessed data. However, if this port is left open with unrestricted inbound access, it can also be used by attackers to remotely execute code, steal sensitive data, or launch distributed denial-of-service (DDoS) attacks.
Here are the remediation steps to ensure there is no unrestricted inbound access to TCP port 11211 (Memcached):
- Review firewall rules and access control lists to identify if any rules are allowing unrestricted inbound access to port 11211.
- If such rules exist, modify them to restrict access to only necessary IP addresses and ports. For example, you can limit access to specific IP addresses, subnets, or VPN connections.
- Consider implementing additional security measures such as two-factor authentication, SSL/TLS encryption, or a web application firewall, especially if the server is publicly accessible.
- Regularly review and update firewall rules and access control lists to ensure they continue to meet security needs and address any new threats or vulnerabilities that may arise.
- Monitor network traffic and logs for any suspicious activity related to port 11211 and investigate any anomalies promptly.
- Consider using security tools that can detect and prevent unauthorized access attempts, such as intrusion detection systems and security information and event management (SIEM) tools.
Note: Remediation steps provided by Lightlytics are meant to be suggestions and guidelines only. It is crucial to thoroughly verify and test any remediation steps before applying them to production environments. Each organization's infrastructure and security needs may differ, and blindly applying suggested remediation steps without proper testing could potentially cause unforeseen issues or vulnerabilities. Therefore, it is strongly recommended that you validate and customize any remediation steps to meet your organization's specific requirements and ensure that they align with your security policies and best practices.