Detect threats to your data stored in RDS databases by using GuardDuty

With Amazon Relational Database Service (Amazon RDS), you can set up, operate, and scale a relational database in the AWS Cloud. Amazon RDS provides cost-efficient, resizable capacity for an industry-standard relational database and manages common database administration tasks.

If you use Amazon RDS for your workloads, you can now use Amazon GuardDuty RDS Protection to help detect threats to your data stored in Amazon Aurora databases. GuardDuty is a continuous security monitoring service that can help you identify and prioritize potential threats in your AWS environment. By analyzing and profiling RDS login activity to your Aurora databases, GuardDuty can detect threats, such as high severity brute force events, suspicious logins, access from Tor, and access by known threat actors.

In this post, we will provide an overview of how to get started with RDS Protection, dive into its finding types, and walk you through examples of how to investigate and remediate findings.

Overview of RDS Protection

RDS Protection in GuardDuty analyzes and profiles Amazon RDS login activity to identify potential threats to your data stored in Aurora databases by using a combination of threat intelligence and machine learning. At launch, RDS Protection supports Aurora MySQL versions 2.10.2 and 3.2.1 or later and Aurora PostgreSQL versions 10.17, 11.12, 12.7, 13.3, and 14.3 or later. An updated list of the supported engines and versions is available in the GuardDuty documentation. RDS Protection doesn’t require additional infrastructure, and you don’t need to configure, collect, or store RDS logs in your own account. RDS Protection is also designed to have no impact on the performance of your database instances so that you don’t have to worry about compromising performance to better secure your data stored in Amazon RDS.

When RDS Protection detects a suspicious or anomalous login attempt that indicates a potential threat to your database instance, GuardDuty generates a finding with details to help you quickly identify relevant information to assist in remediation. RDS Protection findings include details on both anomalous and normal login activity in addition to information such as database instance details, database user details, action information, and actor information. These findings are available to you in the GuardDuty console, AWS Command Line Interface (AWS CLI), and API, and all GuardDuty findings are sent to Amazon EventBridge and AWS Security Hub, giving you options to respond by sending alerts to chat or ticketing systems, or by using AWS Lambda and AWS Systems Manager for automatic remediation.

Enable RDS Protection

Getting started with RDS Protection is simple, and you can do it with just a few steps in the console. Both new and existing GuardDuty customers can take advantage of the GuardDuty RDS Protection 30-day free trial. You can turn RDS Protection on or off for each of your accounts in supported AWS Regions. If you already use GuardDuty, you will need to enable RDS Protection either in the console or CLI, or through the API. You will have the option to enable it in the account that you are currently in, or if you are using a GuardDuty delegated administrator account (as shown in Figure 1), you can enable it for all accounts in your AWS Organizations organization. You’ll also have the ability to auto-enable. The auto-enable feature helps ensure that RDS Protection is enabled for each new account added to your organization, without the need for you to configure anything in each member account. If you are turning on GuardDuty for the first time, RDS Protection is enabled by default.

Figure 1: GuardDuty RDS Protection enablement page

Investigate RDS Protection findings

After GuardDuty generates a finding, you will need to analyze the finding so that you understand the potential impact to your environment. We recommend that you familiarize yourself with the GuardDuty finding types. Understanding GuardDuty finding types can help you understand the types of activity that GuardDuty is looking for and help you prepare for how to respond if they occur in your environment.

As adversaries become more sophisticated, it becomes even more important for you to align to a common framework to understand the tactics, techniques, and procedures (TTPs) behind an individual event. GuardDuty aligns findings using the MITRE ATT&CK framework, which is a globally-accessible knowledge base of adversary tactics and techniques based on real-world observations. GuardDuty findings have a specific finding format that helps you understand the details of each finding. You can examine the Threat Purpose section of the GuardDuty finding types to see finding types associated with various MITRE ATT&CK tactics, including CredentialAccess and Discovery. This can help you identify and understand the type of activity associated with a finding.

For example, consider two finding types that seem similar: CredentialAccess:RDS/MaliciousIPCaller.SuccessfulLogin and Discovery:RDS/MaliciousIPCaller. The difference between them is the ThreatPurpose aspect, located at the beginning of the finding type. GuardDuty has determined that both are involved with MaliciousIPCaller, and the difference is the intent of the activity associated with each finding. CredentialAccess SuccessfulLogin indicates that there was a successful login to your RDS database from a known malicious IP address. Discovery indicates that a threat actor opened a connection to the database, but didn’t attempt to authenticate. This indicates scanning behavior, but it might not be targeted at RDS instances. For more information, see GuardDuty RDS Protection finding types.

GuardDuty uses threat intelligence and machine learning to continually monitor and identify potential threats in your environment. To understand how to investigate RDS Protection finding types, you need to understand the details of a finding type that are derived from machine learning. As shown in Figure 2, RDS Protection finding types have two sections: one that shows the unusual behavior and one that shows the normal, historical behavior. To determine this, GuardDuty uses machine learning models to evaluate API requests to your account and identify anomalous events that are associated with tactics used by adversaries. The machine learning model tracks various factors of the API request, such as the user that made the request, the location the request was made from, and the specific API that was requested. It also looks at information such as successfulLoginCount, failedLoginCount, and incompleteConnectionCount for anomalies based on login activity. For more information about anomalous activity in GuardDuty findings, see Anomalous behavior.

Figure 2: GuardDuty finding details showing unusual and historical behavior sections

With RDS Protection, you now have an additional mechanism to gain insight into your Amazon RDS databases across your accounts to continuously monitor for suspicious activity. RDS Protection can alert you to suspicious activity in Amazon RDS, such as a potentially suspicious or anomalous login attempt, unusual pattern in a series of successful, failed, or incomplete login attempts, and unauthorized access to your database instance from a previously unseen internal or external actor. With this new feature, GuardDuty also extends support for finding types that you might already be familiar with that also apply to RDS databases. These finding types include calls to an RDS database API from a Tor node, or calls to an RDS database from a known malicious IP address, which can indicate that there are interactions with your RDS database from sources that are associated with known malicious activity.

Remediate RDS Protection findings

In this section, we describe two RDS Protection findings and how you can investigate and remediate them. Understanding how to remediate these findings can help you maintain the integrity of your database. We share recommendations that focus specifically on security groups, network access control lists (network ACLs), and firewall rules.

CredentialAccess:RDS/AnomalousBehavior.SuccessfulLogin

The CredentialAccess:RDS/AnomalousBehavior.SuccessfulLogin finding informs you that an anomalous successful login was observed on an RDS database in your AWS environment. It might indicate that a previous unseen user logged in to an RDS database for the first time. A common scenario involves an internal user logging in to a database that is accessed programmatically by applications and not by individual users. A potential malicious actor might have compromised and accessed the role on your RDS database. The default Severity for this finding varies, depending on the anomalous behavior associated with the finding.

Figure 3 shows an example of this finding.

Figure 3: Finding of an anomalous behavior successful login

How to remediate

If the activity is unexpected for the associated database, AWS recommends that you change the password of the associated database user, and review available audit logs for activity that the user performed. Medium and high severity findings might indicate an overly permissive access policy to the database, and user credentials might have been exposed or compromised. We recommend that you place the database in a private virtual private cloud (VPC), and limit the security group rules to allow traffic only from necessary sources. For more information, see Remediating potentially compromised database with successful login events.

We recommend that you take the following steps to remediate this finding:

Remediation step 1: Identify the affected database and user

Identify the affected database and user and confirm whether the behavior is expected or unexpected by looking through the GuardDuty finding details, which provide the name of the affected database instance and the corresponding user details. Use the findings to confirm if the behavior is expected or not—for example, the findings might help you identify a user who logs in to their database instance after a long time has passed; a user who logs in to their database instance only occasionally, such as a financial analyst who logs in each quarter; or a suspicious actor who is involved in a successful login attempt that isn’t authorized and potentially compromises the database instance. Review the IP address of the finding. Public IP addresses might signify overly permissive access if it’s not a known network associated with your account.

Figure 4: Finding with details showing Amazon RDS database instance and user details

If the behavior is unexpected, complete the following steps:

Remediation step 2: Restrict database instance credential access

Restrict database instance access for the suspected accounts and the source of the login activity. For more information, see Remediating potentially compromised credentials and Restrict network access. You can identify the user in the RDS DB user details section within the finding panel in the console, or within the resource.rdsDbUserDetails of the findings JSON. These user details include user name, application used, database accessed, SSL version, and authentication method.

To revoke access or rotate passwords for specific users that are involved in the finding, see Security with Amazon Aurora MySQL or Security with Amazon Aurora PostgreSQL. To securely store and automatically rotate the secrets for RDS databases, use AWS Secrets Manager. For more information, see AWS Secrets Manager tutorials. To manage database users’ access without the need for passwords, use IAM database authentication. For more information, see Security best practices for Amazon RDS.

The following CLI command is an example of how to revoke access to a user in a MySQL database. If the behavior is unexpected, you can revoke the privileges while you assess if the user is malicious.

REVOKE CONNECTION_ADMIN ON *.* FROM 'fakeadmin'@'%';

You can revoke privileges from the user, but when taking this action, you should make sure that the user isn’t vital to your system and that revoking permissions won’t break your production or development application. The following CLI command is an example of how to revoke privileges from a user:

REVOKE ALL PRIVILEGES ON *.* FROM 'fakeadmin'@'%';

If you know that the user isn’t necessary for your database or application to function, then you can remove the user from the system. To make sure that your security team can run forensics, check your company’s incident response policy. If you need help getting started with incident response, see AWS sample incident response playbooks. The following CLI command is an example of how to remove a user:

DROP USER 'fakeadmin'@'%';

Let’s say that you find the behavior unexpected, but the user turns out to be the application user, and making a change to the database credential will break your application. You can use AWS Systems Manager to help in this scenario, in which the affected RDS user is the account that is tied to your application. In many cases, a password rotation can break your application, depending on how you connect. If you rotate the password without notifying your application, the application might require additional cascading changes. You could lose connectivity to your application because the credentials that your application is using to connect to your database didn’t change, and now you are experiencing an outage that will remain until you update the credentials. Systems Manager can tie into your application code to automatically update the rotated database credentials in your application. For more information, see Rotate Amazon RDS database credentials automatically with AWS Secrets Manager.

The following figure shows a CLI command to get a secret from Secrets Manager — for this example, we assume the secret is compromised.

Figure 5: Example compromised credentials

The following figures shows that we have a new set of credentials that replace our old credentials, as indicated by “CreatedDate”.

Figure 6: Example remediated credentials

Remediation step 3: Assess the impact and determine what information was accessed

If available, review the audit logs to identify which information might have been accessed. For more information, see Monitoring events, logs, and streams in an Amazon Aurora DB cluster. Determine if sensitive or protected information was accessed or modified.

Remediation step 4: Restrict database instance network access

Restrict database instance access for the suspected accounts and the source of the login activity. For more information, see Remediating potentially compromised credentials and Restrict network access.

To learn how to restrict IP access on a security group, see Control traffic to resources using security groups. You can identify the user in the RDS DB user details section within the finding panel in the console, or within the resource.rdsDbUserDetails of the findings JSON. These user details include user name, application used, database accessed, SSL version, and authentication method.

Remediation step 5: Perform root-cause analysis and determine the steps that potentially led to this activity

Implementing a lessons-learned framework and methodology can help improve your incident response capabilities and also help prevent the incident from recurring. By learning from each incident, you can help avoid repeating the same mistakes, exposures, or misconfigurations, which can both improve your security posture and reduce the time lost to preventable situations. To learn more about post-incident activity, see AWS Security Incident Response Guide.

You can set up an alert to be notified when an activity modifies a networking policy and creates an insecure state by using AWS Config and Amazon Simple Notification Service (Amazon SNS). You can use an EventBridge rule with a custom event pattern and an input transformer to match an AWS Config evaluation rule output as NON_COMPLIANT. Then, you can route the response to an Amazon SNS topic. For more information, see How can I be notified when an AWS resource is non-compliant using AWS Config? or Firewall policies in AWS Network Firewall.

CredentialAccess:RDS/AnomalousBehavior.SuccessfulBruteForce

The CredentialAccess:RDS/AnomalousBehavior.successfulBruteForce finding informs you that an anomalous login occurred that is indicative of a successful brute force event, as observed on an RDS database in your AWS environment. Before the anomalous successful login, a consistent pattern of unusual failed login attempts was observed. This indicates that the user and password associated with the RDS database in your account might have been compromised, and a potentially malicious actor might have accessed the RDS database. The Severity of this finding is high. Figure 7 shows an example of this finding.

Figure 7: Example of an anomalous successful brute force finding

How to remediate

This activity indicates that database credentials might have been exposed or compromised. We recommend that you change the password of the associated database user, and review available audit logs for activity performed by the potentially compromised user. A consistent pattern of unusual failed login attempts indicates an overly permissive access policy to the database, or that the database might also have been publicly exposed. AWS recommends that you place the database in a private VPC, and limit the security group rules to allow traffic only from necessary sources. For more information, see Remediating potentially compromised database with successful login events.

We recommend that you take the following steps to remediate this finding

Remediation step 1: Identify the affected database and user

The generated GuardDuty finding provides the name of the affected database instance and the corresponding user details. For more information, see Finding details.

Figure 8: Finding details showing Amazon RDS database instance and user details

Remediation step 2: Identify the source of the failed login attempts

In the generated GuardDuty finding, you can find the IP address, and if it was a public connection, the ASN organization in the Actor section of the finding panel. An autonomous system is a group of one or more IP prefixes (lists of IP addresses accessible on a network) run by one or more network operators that maintain a single, clearly-defined routing policy. Network operators need autonomous system numbers (ASNs) to control routing within their networks and to exchange routing information with other internet service providers.

Figure 9: Action and actor details related to GuardDuty brute force finding

Remediation step 3: Confirm that the behavior is unexpected

Examine if this activity represents an attempt to gain additional unauthorized access to the database instance as follows:

• If the source is internal to your network, examine if an application is misconfigured and attempting a connection repeatedly.
• If this is an external actor, examine whether the corresponding database instance is public facing or is misconfigured and thus allowing potential malicious actors to attempt to log in with common user names.

If the behavior is unexpected, complete the following steps:

Remediation step 4: Restrict database instance access

Restrict database instance access for the suspected accounts and the source of the login activity. For more information, see Remediating potentially compromised credentials and Restrict network access.

As discussed previously for the CredentialAccess:RDS/AnomalousBehavior.SuccessfulLogin finding, you can restrict access to the database through credentials or network access:

• For information about how to restrict a specific user’s database access, see Restrict database instance credential access.
• For information about how to restrict network access to the database, see Restrict database instance network access.

Remediation step 5: Perform root-cause analysis and determine the steps that potentially led to this activity

By learning from each incident, you can help avoid repeating the same mistakes, exposures, or misconfigurations, which can both improve your security posture and reduce time lost to preventable situations.

Conclusion

In this post, you learned about the new GuardDuty RDS Protection feature and how to understand, operationalize, and respond to the new findings. You can enable this feature through the GuardDuty console, CLI, or APIs to start monitoring your Amazon RDS workloads today.

If you’ve created EventBridge rules to send findings from GuardDuty to a target, make sure that you’ve configured your rules to deliver the newly added findings. After you enable GuardDuty findings, consider creating IR playbooks, doing tabletops and AWS gamedays, and mapping out what you want to automate. For more information, see the AWS Security Incident Response Guide and AWS Incident Response Playbook resources. To gain hands-on experience with different AWS Security services, see AWS Activation Days. The Activation Days workshops begin with hands-on work with different services in sandbox accounts, and then take you through the steps to deploy them across your organization.

To make it more efficient for you to operate securely on AWS, we are committed to continually improving GuardDuty, and we value your feedback. If you have feedback about this post, submit comments in the Comments section below. If you have questions about this post, start a new thread on AWS re:Post or contact AWS Support.

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