Waf

Protecting Logins and Signups with Fraud Control

Overview

Domain expertise for AWS WAF Fraud Control: the Account Takeover Prevention (ATP) managed rule group for login protection and the Account Creation Fraud Prevention (ACFP) managed rule group for signup protection. Covers why rate limiting misses this abuse, the mandatory application integration SDK, the CloudFront-only limitation on response inspection and its workaround, and the Count-first tuning path.

Does not cover generic rate limiting (the rate-based reference) or bot detection (the bot references). Those are separate.

Execute commands using the AWS MCP server when connected (sandboxed execution, audit logging, observability). Fall back to the AWS CLI otherwise.

Table of Contents

• Overview

• Workflow

• Decision: ATP, ACFP, or both

• The SDK is mandatory

• Response inspection is CloudFront only

• Count mode first

• Troubleshooting

• Procedure

• Security Considerations

• Additional Resources

Workflow

To protect logins and signups end to end, follow the procedure exactly. See the Procedure section below.

The procedure covers:

• Adding ATP for login protection, ACFP for signup protection, or both

• Integrating the application integration SDK

• Configuring request inspection (and response inspection where supported)

• Running in Count mode, then mapping labels to actions

Decision: ATP, ACFP, or both

Constraints:

• You MUST reach for ATP and ACFP for account-based abuse rather than rate-based rules; the abuse is distributed and low-rate per source, so rate limiting misses it

• You SHOULD configure the login path for ATP and both the registration page and creation paths for ACFP

The SDK is mandatory

Both rule groups rely on session tokens that the application integration SDK issues. Without it the protection is weak.

Constraints:

• You MUST treat the application integration SDK as mandatory for ATP and ACFP, not optional

• You SHOULD confirm the SDK is integrated before relying on these rule groups

Response inspection is CloudFront only

Response inspection (tracking login success and failure) is available only on web ACLs protecting CloudFront distributions.

Constraints:

• You MUST tell the customer that on an Application Load Balancer the response-based rules such as VolumetricIpFailedLoginResponseHigh and VolumetricSessionFailedLoginResponseHigh will not fire

• You SHOULD offer the workaround of putting CloudFront in front of the Application Load Balancer when response inspection is needed

Count mode first

Turning these rule groups straight to Block risks locking out real users on a busy login page.

Constraints:

• You MUST run ATP and ACFP in Count mode first, review the labeled traffic, then map labels to actions before enforcing

Troubleshooting

Credential stuffing gets through despite a rate limit

Rate limiting misses distributed, low-rate account abuse. Add ATP (Decision: ATP, ACFP, or both).

Response-based rules never fire on an ALB

Response inspection is CloudFront only. Put CloudFront in front of the ALB (Response inspection is CloudFront only).

Protection is weak even with ATP enabled

The SDK is not integrated. Integrate it (The SDK is mandatory).

Procedure

Overview

This procedure adds ATP, ACFP, or both with the SDK, configures inspection, runs in Count, then maps labels to actions, and surfaces the console link.

Parameters

• web_acl_name, web_acl_id, scope (required): Identify the web ACL.

• rule_groups (required): ATP, ACFP, or both.

• login_path (required for ATP): The login endpoint path.

• registration_path and creation_path (required for ACFP): The signup paths.

Constraints for parameter acquisition:

• You MUST ask for all required parameters upfront in a single prompt

• You MUST confirm the application integration SDK is integrated and logging is on

Steps

1. Verify dependencies

Constraints:

• You MUST confirm credentials with aws sts get-caller-identity

• You MUST confirm the SDK is integrated and logging and sampling are on

• You SHOULD confirm whether the resource is CloudFront (response inspection) or an ALB (request inspection only)

2. Add the rule groups in Count mode

Constraints:

• You MUST add ATP with the login path, and ACFP with both the registration and creation paths, configuring request inspection for the username, password, and (ACFP) email fields

• You MUST configure response inspection only on a CloudFront web ACL

• You MUST fetch the current LockToken before update-web-acl and pass the full rule set

• You MUST preserve the web ACL's existing DefaultAction from the get-web-acl response and pass it back as {default_action}; do not assume Allow={}, since that would silently open all unmatched traffic on a web ACL whose default action is Block. For example, adding ATP with request inspection on the login path:

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  aws wafv2 get-web-acl --name {web_acl_name} --scope {scope} --id {web_acl_id} --region {region}
  aws wafv2 update-web-acl --name {web_acl_name} --scope {scope} --id {web_acl_id} \
    --lock-token {lock_token} --default-action {default_action} \
    --rules '[{"Name":"AWS-ATP","Priority":1,"Statement":{"ManagedRuleGroupStatement":{"VendorName":"AWS","Name":"AWSManagedRulesATPRuleSet","ManagedRuleGroupConfigs":[{"AWSManagedRulesATPRuleSet":{"LoginPath":"{login_path}","RequestInspection":{"PayloadType":"JSON","UsernameField":{"Identifier":"/username"},"PasswordField":{"Identifier":"/password"}}}}]}},"OverrideAction":{"Count":{}},"VisibilityConfig":{"SampledRequestsEnabled":true,"CloudWatchMetricsEnabled":true,"MetricName":"AWS-ATP"}}]' \
    --visibility-config SampledRequestsEnabled=true,CloudWatchMetricsEnabled=true,MetricName={web_acl_name} \
    --region {region}

  ACFP uses AWSManagedRulesACFPRuleSet with RegistrationPagePath, CreationPath, and its own RequestInspection (including the email field); add a ResponseInspection block only on a CloudFront web ACL

3. Review and map labels to actions

Constraints:

• You MUST review the Count-mode labels (such as the compromised-credential label) before enforcing

• You MUST map labels to actions and switch to enforcement once validated

4. Surface the console link

Constraints:

• You MUST present the web ACL console link and tell the customer to confirm the Fraud Control rules and their actions:

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  https://us-east-1.console.aws.amazon.com/wafv2/homev2/web-acls?region={region}

Example

Example input

{
  "web_acl_name": "example-cf-webacl",
  "web_acl_id": "abc",
  "scope": "CLOUDFRONT",
  "rule_groups": ["ATP"],
  "login_path": "/api/login"
}

Example output

Confirmed the SDK is integrated and the resource is CloudFront, so response inspection is available.
Added ATP on /api/login with request and response inspection, in Count.
Reviewed labels, mapped the compromised-credential label to Block, then enforced.
Open the web ACL and confirm the Fraud Control rules:
https://us-east-1.console.aws.amazon.com/wafv2/homev2/web-acls?region=us-east-1

Troubleshooting

Credential stuffing gets through

Rate limiting misses it. Add ATP (Step 2).

Response rules never fire on an ALB

Response inspection is CloudFront only. Front the ALB with CloudFront (Step 1).

Security Considerations

This procedure modifies a security control, so misconfiguration directly weakens the application's defenses.

• Least-privilege IAM. You MUST grant only the specific wafv2: actions a task needs (for example wafv2:GetWebACL and wafv2:UpdateWebACL) rather than wafv2:* or the AWSWAFFullAccess managed policy.

• Ephemeral credentials. You MUST use IAM roles with temporary credentials (such as an EC2 instance profile, SSO session, or aws sts assume-role) rather than long-lived IAM user access keys when running these WAF CLI commands.

• Monitor configuration changes. You SHOULD enable AWS CloudTrail on wafv2 management events and set CloudWatch alarms on critical web ACL configuration changes (such as DeleteWebACL and UpdateWebACL rule removals) and on the web ACL's BlockedRequests and CountedRequests metrics, so rule changes and sudden spikes in blocked or counted traffic are detected.

Additional Resources

• AWS WAF Fraud Control account takeover prevention (ATP) rule group (AWS WAF Developer Guide)

• AWS WAF Fraud Control account creation fraud prevention (ACFP) rule group (AWS WAF Developer Guide)

• ATP example: Response inspection configuration (AWS WAF Developer Guide)

• Testing and tuning your AWS WAF protections (AWS WAF Developer Guide)