Rule: Configure Application Load Balancers to Drop HTTP Headers
This rule emphasizes the configuration of Application Load Balancers to drop HTTP headers for improved security measures.
| Rule | Application load balancers should be configured to drop HTTP headers |
| Framework | AWS Foundational Security Best Practices |
| Severity | ✔ Medium |
Rule Description
According to AWS Foundational Security Best Practices, it is recommended to configure application load balancers to drop certain HTTP headers. This rule helps to enhance security by preventing information leakage or potential vulnerabilities that may arise from insecure header configurations.
Troubleshooting Steps
If you encounter any issues or errors while configuring the application load balancer to drop HTTP headers, follow these troubleshooting steps:
- 1.Double-check the load balancer configuration and ensure that the specified headers to be dropped are correct.
- 2.Verify that the load balancer is associated with the correct target group and that the target group is correctly configured.
- 3.Check if there are any conflicts or misconfigurations in the ACL (Access Control List) rules or security group settings associated with the load balancer.
- 4.Ensure that the health checks for the target instances associated with the load balancer are passing successfully.
- 5.Review the load balancer access logs and CloudWatch metrics for any relevant error messages or anomalies.
If the issue persists, refer to AWS documentation or consider seeking assistance from AWS support for further guidance.
Necessary Codes
In order to configure the application load balancer to drop HTTP headers, you need to create or modify a Load Balancer Listener Rule. The following code snippet demonstrates an example listener rule using AWS Command Line Interface (CLI):
aws elbv2 create-rule --listener-arn <listener-arn> --priority 10 --actions Type=forward,TargetGroupArn=<target-group-arn> --conditions Field=http-header,HttpRequestHeaders=<header-to-drop1>,Values=<header-value1>,<header-value2> Field=http-header,HttpRequestHeaders=<header-to-drop2>,Values=<header-value3>
Replace
<listener-arn><target-group-arn><header-to-drop1><header-to-drop2><header-value1><header-value2><header-value3>Step-by-Step Guide for Remediation
Follow these steps to configure the application load balancer to drop HTTP headers:
- 1.Identify the specific HTTP headers that should be dropped for your application load balancer. Refer to your organization's security policies or best practices.
- 2.Access the AWS Management Console and navigate to the EC2 service.
- 3.Select "Load Balancers" from the left navigation panel.
- 4.Choose the application load balancer you want to configure.
- 5.Select the "Listeners" tab and identify the listener to which you want to add or modify a rule.
- 6.Click on the "View/edit rules" link next to the listener.
- 7.Click on the "Add rule" button to create a new rule or select an existing rule to modify.
- 8.Configure the rule conditions by selecting the appropriate field as "http-header" and specifying the HTTP header name and its associated values that should trigger the drop action.
- 9.Configure the rule action as "forward" and select the target group that corresponds to your application instances.
- 10.Review the rule and click on the "Create" or "Save" button to apply the changes.
- 11.Optional: Test the configuration by accessing your application through the load balancer and verifying that the specified headers are being dropped.
By following these steps, you will be able to configure the application load balancer to drop HTTP headers as per the AWS Foundational Security Best Practices.