Help Center> Host Security Service (New)> FAQs> Brute-force Attack Defense> What Do I Do If HSS Frequently Reports Brute-force Alarms?
Updated on 2024-01-16 GMT+08:00

What Do I Do If HSS Frequently Reports Brute-force Alarms?

An alarm indicates that an attack was detected. It does not mean your cloud servers have been intruded. If you receive an alarm, handle it and take countermeasures in a timely manner.

Possible Causes

No access control is configured for the ports used for remotely connecting to your servers. As a result, viruses on the network frequently attacked your ports.


Take any of the following measures.

  • Configure the SSH login whitelist.

    The SSH login whitelist allows logins from only whitelisted IP address, effectively preventing account cracking. For details, see Configuring an SSH Login IP Address Whitelist.

  • Enable 2FA.

    2FA requires users to provide verification codes before they log in. The codes will be sent to their mobile phones or email boxes.

    Choose Installation & Configuration. On the Two-Factor Authentication tab, select servers and click Enable 2FA. For details, see Enabling 2FA.

  • Use non-default ports.

    Change the default remote management ports 22 and 3389 to other ports.

  • Configure security group rules to prevent the attacking IP addresses from accessing your service ports.

    You are advised to allow only specified IP addresses to access open remote management ports (for example, for SSH and remote desktop login).

    You can configure security group rules to control access to your servers. For a port used for remote login, you can set IP addresses that are allowed to remotely log in to your ECSs.

    To allow IP address to remotely access Linux ECSs in a security group over the SSH protocol and port 22, you can configure the following security group rule.

    Table 1 Setting IP addresses to remotely connect to ECSs






    SSH (22)


    For example,

  • Set a strong password.

    Password policy check and weak password detection can find accounts that use weak passwords on your servers. You can view and handle password risks on the console.

How Does HSS Intercept Brute Force Attacks?

HSS can detect brute-force attacks on SSH, RDP, FTP, SQL Server, and MySQL accounts.

By default, HSS will block an IP address if it has five or more brute-force attack attempts detected within 30 seconds, or 15 or more brute-force attack attempts detected within 3600 seconds.

If you have enabled an edition higher than HSS basic, you can configure a login security policy to specify the brute force cracking determination mode and blocking duration. For details, see Login Security Check.

To view the IP addresses blocked by HSS, choose Detection > Alarms and click the value above Blocked IP Addresses.

Brute-force Attack Defense FAQs