How to deal with brute force attacks on cloud servers?

To deal with brute force attacks on cloud servers, you can implement the following measures:

1. Use Strong Passwords and Multi-Factor Authentication (MFA)

   • Enforce complex passwords with a mix of uppercase, lowercase, numbers, and special characters.
   • Enable MFA to add an extra layer of security, requiring a second verification step (e.g., SMS code or authentication app).

2. Limit Login Attempts

   • Configure fail2ban or similar tools to automatically block IP addresses after multiple failed login attempts.
   • Example: If an IP fails SSH login 5 times within 10 minutes, block it for 30 minutes.

3. Disable Unused Ports and Services

   • Close unnecessary ports (e.g., FTP, Telnet) to reduce attack surfaces.
   • Only allow essential services (e.g., SSH on port 22, HTTP/HTTPS on ports 80/443).

4. Use SSH Key Authentication Instead of Passwords

   • Replace password-based SSH logins with SSH keys, which are harder to brute-force.
   • Example: Generate an SSH key pair (ssh-keygen) and add the public key to the server’s ~/.ssh/authorized_keys.

5. Firewall and Security Group Rules

   • Restrict access to specific IP ranges (e.g., allow only your office IP for SSH).
   • Use cloud provider firewalls (e.g., Tencent Cloud Security Group) to block suspicious traffic.

6. Monitor and Log Suspicious Activity

   • Use tools like fail2ban, logwatch, or cloud-native monitoring (e.g., Tencent Cloud Cloud Monitor) to detect and respond to attacks.
   • Example: Set up alerts for repeated failed login attempts.

7. Regularly Update and Patch Systems

   • Keep the OS and software updated to fix vulnerabilities that attackers might exploit.

For Tencent Cloud users, leverage Tencent Cloud Security Group, Cloud Monitor, and Host Security (CWP) to enhance protection against brute force attacks. These services provide automated threat detection, firewall management, and vulnerability scanning.