As AI agents and automated tools increasingly access web applications, distinguishing legitimate bot traffic from malicious attempts has become a critical security challenge. Traditional approaches such as IP-based filtering and reverse DNS lookups fail in multi-tenant systems (such as Amazon Bedrock AgentCore) where thousands of distinct workloads share the same IP space. Attackers can easily spoof user agents, and manual allowlists don’t scale with growing demand.

Web Bot Authentication (WBA), available in AWS WAF Bot Control since November 2025, solves this challenge by implementing cryptographic signatures that provide tamper-proof verification of bot identities. WBA uses asymmetric cryptography to verify that a request comes from an authorized automated agent, relying on two active Internet Engineering Task Force (IETF) drafts: a directory draft for sharing public keys, and a protocol draft defining how keys attach crawler identity to HTTP requests.

With WBA, you can confidently identify trusted automated access while maintaining granular control through WAF labels, creating a more secure and manageable ecosystem for both bot operators and website owners. AWS WAF Bot Control respects WBA verification status by default, automatically allowing verified AI agent traffic.

This post provides a deeper technical guide to implementing WBA with AWS WAF. You learn how WBA works, explore the new labels and capabilities it introduces, and walk through a step-by-step implementation—including signing code—to authenticate bot traffic using cryptographic signatures.

How Web Bot Authentication works with AWS WAF

WBA uses asymmetric cryptography to verify bot identities through HTTP message signatures. The process works as follows:

1. Bot registration – Bot operators publish their public keys in a signature directory. AWS WAF regularly polls these directories and maintains a valid key registry.
2. Request signing – Each bot operator’s request is signed using their private key following the IETF standard HTTP Message Signatures (RFC 9421).
3. Verification – AWS WAF verifies signatures against known public keys associated with the bot operator and appends labels related to verification status.

A typical WBA-signed request includes headers like the following:

Signature-Agent: https://signature-agent.test
Signature-Input: sig2=("@authority" "signature-agent")
;created=1735689600
;keyid="poqkLGiymh_W0uP6PZFw-dvez3QJT5SolqXBCW38r0U"
;alg="ed25519"
;expires=1735693200
;nonce="e8N7S2MFd/qrd6T2R3tdfA..."
;tag="web-bot-auth"
Signature: sig2=:jdq0SqOwHdyHr9+r5jw3iYZH6aNGKijYp/EstF4RQ..

The following sequence diagram shows how AWS WAF verifies bot signatures and applies labels for allow or block decisions.

Figure 1 – AWS WAF Web Bot Authentication verification flow

The workflow shown in figure 1 includes the following steps:

1. A bot sends a signed request to Amazon CloudFront and is inspected by AWS WAF Bot Control
2. AWS WAF Bot Control retrieves the bot operator’s public key from the signature directory
3. AWS WAF Bot Control verifies the ed25519 signature
4. AWS WAF Bot Control appends a verification label (verified, invalid, expired, or unknown_bot)

AWS WAF Bot Control evaluates rules using the label to allow or block the request.

New capabilities added to AWS WAF

With the addition of WBA, the following capabilities were added to AWS WAF.

Cryptographic bot verification

When a bot sends a request, it includes HTTP message signatures that AWS WAF validates at the edge using the AWS WAF Bot Control rule group (version 4.0 and later). This validation process adds minimal latency to requests while providing cryptographic certainty about the bot’s identity. HTTP Message Signatures is an open IETF standard (RFC 9421) that defines a mechanism for signing and verifying HTTP messages using asymmetric keys—in practice, this means a bot cryptographically signs specific headers and metadata of each request, and the receiver can verify the signature using the bot’s published public key.

New labels within AWS WAF for granular control

AWS WAF automatically validates signatures, and successfully validated traffic is immediately marked as verified. This verification status can be used in WAF rules and bot management policies, giving you the ability to write your own rules based on the new functionality.

The following table describes the new labels.

AWS WAF now automatically allows verified AI agent traffic

AWS WAF Bot Control now respects WBA verification status by default, automatically allowing verified AI agent traffic. This includes two specific behavior changes:

• Category:AI rule update – Previously, the Category:AI rule under common Bot Control blocked unverified bots. Bot Control now checks WBA verification status before applying this rule.
• TGT_TokenAbsent rule update – The TGT_TokenAbsent rule, which detects requests without a WAF token, no longer matches requests that carry the web_bot_auth:verified label.

Key benefits for AWS WAF customers

WBA with AWS WAF delivers several advantages for organizations managing automated traffic at scale.

• Enhanced bot visibility – Clear identification of distinct bots operating from multi-tenant platforms like Amazon Bedrock AgentCore, providing transparency into automated traffic sources. The AWS WAF console includes a new AI activity dashboard that provides a centralized view of AI bot and agent traffic across your protected resources.
• Enhanced security – Cryptographic verification of bot identities using industry-standard signing mechanisms.
• Reduced false positives – Accurate distinction between legitimate and malicious automated traffic, particularly in shared IP environments.
• Industry alignment – Alignment with industry standards and major content delivery network (CDN) providers for consistent bot authentication across platforms.

Customer use cases for WBA with AWS WAF

Across industries, organizations use WBA to grant automated agents secure, controlled access to their web applications. The following scenarios highlight where this capability delivers real-world value:

• Verified customer support agents – Authenticate AI-powered chat and support bots so websites can recognize them as approved, registered agents. This enables seamless customer service automation while maintaining security controls and audit trails.
• Automated crawling and indexing – Allow search engine crawlers and content indexers to fetch pages with clear identity and scoped permissions. This reduces false-positive blocks, improves crawl efficiency, and helps legitimate bots access your content without triggering security controls.
• Partner integrations – Third-party agents can access customer portals and APIs with explicit consent and granular, scoped access controls. This facilitates secure business-to-business (B2B) integrations while maintaining visibility into partner bot activity.
• Enterprise automations and agents – Internal automation tools—including monitoring systems, QA bots, continuous integration and delivery (CI/CD) pipelines, and robotic process automation (RPA) solutions—get authenticated access to web applications with least-privilege access principles and full auditability.

Availability

WBA was introduced in Bot Control rule group Version_4.0 (November 2025) for Amazon CloudFront distributions, with continued support in later versions. With Version_6.0, WBA is available for resource types supported by AWS WAF across standard commercial AWS Regions.

Getting started: Developers or agents quick start

Whether you’re implementing WBA yourself or working with an AI coding assistant, the following steps walk you through deploying WBA, signing requests, and writing custom rules.

Step 1: Deploy the WBA-enabled Bot Control

Add the AWS WAF Bot Control rule group to your CloudFront-associated web ACL using static Version_4.0 or Version_5.0—both include WBA support for cryptographic bot verification. Version_5.0 (released February 2026) covers more than 650 unique bots and agents spanning categories including AI search engine crawlers, AI data collectors, AI assistants, and large language model (LLM) training crawlers.

Important: You must explicitly select one of these static versions.

The following example CloudFormation YAML snippet shows a bot control rule set configuration:

# Bot Control rule group with WBA support
ManagedRuleGroupStatement:
  VendorName: AWS
  Name: AWSManagedRulesBotControlRuleSet
  # Use Version_4.0 or higher for WBA support
  Version: Version_5.0
  ManagedRuleGroupConfigs:
    - AWSManagedRulesBotControlRuleSet:
        # COMMON level provides WBA verification
        # TARGETED level adds additional bot-specific protections
        InspectionLevel: COMMON

Step 2: Sign requests from your bot

If your agent runs on Amazon Bedrock AgentCore Browser, request signing is handled automatically—no additional configuration is required.

For agents running outside of AgentCore, registration APIs are on the roadmap that you can use to sign requests independently by:

1. Generating an ed25519 key pair
2. Hosting your public key in a signature directory
3. Signing outbound HTTP requests using the Signature-Input and Signature headers with the web-bot-auth tag. For language-specific signing implementations, see the HTTP Message Signatures RFC (RFC 9421) and the AWS WAF Bot Control documentation.

Step 3: Write custom rules using WBA labels

Use the verification labels in custom WAF rules for granular traffic control, for example:

• Allow – awswaf:managed:aws:bot-control:bot:web_bot_auth:verified
• Rate-limit – awswaf:managed:aws:bot-control:bot:web_bot_auth:invalid
• Alert on – awswaf:managed:aws:bot-control:bot:web_bot_auth:expired

Step 4: Monitor WBA traffic

Use AWS WAF metrics and logs to monitor authenticated bot traffic:

• Review Amazon CloudWatch metrics for Bot Control rule group matches and set up alarms for anomalous or unexpected spikes in invalid or expired verification attempts.
• Analyze AWS WAF logs to identify patterns in bot authentication attempts and filter on web_bot_auth labels.
• Use the AI Activity Dashboard in the AWS WAF console for a centralized view of AI bot traffic. Visualize traffic trends, identify top bots and frequently targeted paths, and filter by verification status to decide which bots to allow, rate-limit, or block.

Conclusion

WBA with AWS WAF provides a cryptographically secure, standards-based approach to authenticating legitimate AI agent traffic. By moving from IP-based allowlisting to signature-based verification, you gain accurate bot identification that works across multi-tenant environments.

Looking ahead, our focus is to simplify bot authentication and make it safer by default. Registration APIs that agent owners can use to cryptographically verify bot identity and intent are on the roadmap, helping website owners quickly distinguish trusted automation from unknown traffic.

If you own an agent, adopt WBA and register your agent to receive verified status. In parallel, AWS continues to actively participate in the IETF web-bot-auth working group, advocating for complementary approaches—using both identifying and anonymous verification protocols—and will incorporate these standards into products as they mature to help your deployments stay aligned with the broader ecosystem.

To get started, see the AWS WAF Bot Control documentation and the HTTP Message Signatures RFC (RFC 9421).

If you have feedback about this post, submit comments in the Comments section below.

Today, you can use AWS Network Firewall to protect traffic flowing to and from containerized applications on Amazon Elastic Kubernetes Service (Amazon EKS) and Amazon Elastic Container Service (Amazon ECS) clusters. If you run AI and machine learning (ML) workloads on Amazon EKS—such as model inference, RAG pipelines, or JupyterHub—your containerized workloads require the same firewall protections you enforce for traditional applications. However, traditional firewall rules rely on IP addresses, and pod IPs in Kubernetes change frequently as containers scale or restart. Writing and maintaining static firewall rules based on these ephemeral IPs, CIDRs, and subnets is difficult and error-prone, which can leave gaps in your security posture.

Kubernetes Network Policies offer basic traffic control at the namespace level, operating at layers 3 and 4. Depending on your security requirements, you might need additional capabilities beyond what network policies provide: Layer 7 inspection, FQDN-based filtering, and protection from threats detected by managed IDS/IPS rules. Visibility into which pod or service generates blocked traffic is equally important, so you can troubleshoot faster and meet audit requirements.

You can use container attribute-based rules for Network Firewall to define firewall rules for your containerized workloads on both Amazon EKS and Amazon ECS using native container attributes, rather than relying on ephemeral IP addresses. For Amazon EKS, these attributes include namespaces, pod names, cluster names, and labels. This reduces the need to maintain IP-based rules in dynamic container environments. While this capability supports both Amazon EKS and Amazon ECS, this post focuses on Amazon EKS. Your containerized workloads get the same Network Firewall capabilities you use today.

There is no additional charge for the feature itself, because it’s included in the base tier of Network Firewall.

When you create a container association and link it to your EKS cluster, Network Firewall automatically discovers and tracks the pods that match your defined attributes (namespace, labels, cluster name) and resolves them to their current IP addresses. As pods scale up or restart, the firewall dynamically updates the IP-to-attribute mapping in near real-time and no manual rule updates are required. This approach keeps your firewall rules accurate in dynamic environments while minimizing performance impact on the EKS cluster. In multi-cluster environments, this feature enables centralized cross-cluster traffic inspection for any traffic that passes through the firewall.

Container attribute-based rules also enrich firewall alert logs with container context. Alert logs now include a new metadata field with the container association name associated with the matched rule. This gives security teams the ability to trace blocked, allowed, or alerted traffic directly back to the originating workload. Network Firewall exports these enriched logs to Amazon CloudWatch Logs and Amazon Simple Storage Service (Amazon S3), from where you can forward them to the SIEM of your choice. To bind these attribute groups to running workloads, Network Firewall continuously watches your EKS cluster for pod lifecycle events (create and delete) across the namespaces covered by your container association definition. This definition is stored in a container association, keyed by attribute name and value.

When published, you reference these @ aliases in stateful Suricata rules. The following are some common patterns:

• Pod group rules: Allow only payment-service pods to reach the external payment gateway over TLS:

  pass tls @ecommerce_pods any -> any 443 (msg:"allow ecommerce to payment gateway"; tls.sni; content:“checkip.amazonaws.com”; flow:to_server,established; sid:1; rev:1;)

• Layer 7 application rules : Enforce block from all pods from reaching malicious destinations:

  drop tls @all-pods any -> $EXTERNAL_NET any (msg:"Block malicious sites"; aws_domain_category:malicious-sites; sid:10; rev:1;)

At packet evaluation time, Network Firewall expands each @ reference against the current catalog. When pods scale, restart, or move between nodes, the controller refreshes group membership, and the firewall picks up the new IPs, hence no rule edits or operator intervention is required. Each match—whether alert, pass, or drop—streams to the logging destination of your choice with container context. This gives your team a real-time, auditable view of policy effectiveness and a feedback loop for tuning rules and pod-group definitions over time.

The Network Firewall container attribute-based rules for Amazon container workloads can be configured using the AWS Management Console for Amazon Virtual Private Cloud (Amazon VPC), AWS Command Line Interface (AWS CLI), or AWS SDK by creating a container association. This container association then can be used to create attribute-based Network Firewall rules.

This walkthrough requires an existing Network Firewall configured to filter traffic through your Amazon VPC. If you haven’t set one up yet, see Getting started with AWS Network Firewall.

Step 1 – Create a container association:

1. In the AWS VPC console, navigate to Network Firewall, select Container associations. Choose Create container association.
2. Enter a Name and optional Description for this container association.
3. Under Cluster configuration, select the Cluster type and select your EKS cluster from the Cluster drop down.
4. For Attribute filters, configure the EKS attribute to identify which pods to associate:
   • Attribute key: Enter the attribute key defined in your EKS cluster (for example, namespace, pod, cluster, or custom label key).
   • Attribute value: Enter an attribute key value defined in your EKS cluster.

Figure 1: Create container association

Step 2 – Create an attribute-based firewall rule:

1. In the AWS VPC console, navigate to Network Firewall, then select Network Firewall rule groups.
2. Select Create rule group.
3. For Rule group type, select Stateful rule group.
4. For Rule group format, select Suricata compatible rule string.
   
   

   Figure 2: Rule group selection

5. For Rule evaluation order, select Strict order. Choose Next.
6. Under Describe rule group, enter a Name, Description, and Capacity for the rule group. Choose Next.
   
   

   Figure 3: Describe rule group

7. Under IP set references, enter a variable name and from the resource ID drop-down, select the container association created in step 1.
8. Under Suricata compatible rule string, enter your Suricata rule string. The following is a sample string used for this post:

   pass tls @ecommerce_pods any -> any any (msg:"allow ecommerce to payment gateway"; flow:to_server; tls.sni; dotprefix; content:".checkip.amazonaws.com"; endswith; nocase; alert; sid:101; rev:1;)
   
   reject tls @ecommerce_pods any -> any 443 (msg:"block ecommerce pods to external ecommerce website"; flow:to_server; tls.sni; dotprefix; content:".amazon.com"; endswith; nocase; alert; sid:104; rev:1;)

   

   Figure 4: Configure rules

9. Choose Next.
10. Enter the details if required on the next options. For this post, we’re using the default values.
11. On the review and create page, choose Create rule group.

To verify these rules are working as expected, test using the curl command on a pod in the ecommerce namespace. A curl request to www.amazon.comshould fail, because action=rejectis defined in the Suricata rule string. Similarly, a request to the payment gateway URL should succeed, because action=passis defined in the Suricata rule string.

Test 1 – Allowed traffic:

kubectl exec -n ecommerce deployment/payment-service -- curl -sk --max-time 5 -w "\nHTTP_CODE:%{http_code}\n" https://checkip.amazonaws.com/

HTTP_CODE:200

Test 2 – Blocked traffic:

kubectl exec -n ecommerce deployment/payment-service -- curl -sk --max-time 5 https://www.amazon.com 2>&1

curl: (35) Recv failure: Connection reset by peer
command terminated with exit code 35

Container association can also be used in a Standard stateful rules format.

There are several important considerations when adopting this feature.

1. Source NAT (SNAT) must be disabled so that the Network Firewall can see pod IP addresses. If SNAT remains enabled, only the node IP will be visible, preventing granular pod-level egress controls.
2. This feature can’t enforce security on pod-to-pod traffic within the same node, because that traffic doesn’t traverse the Network Firewall endpoint. A separate solution is needed for this use case.
3. Performance impact can vary based on rule complexity and traffic volume.

In this post, you learned how container attribute-based rules for AWS Network Firewall solve the challenge of securing dynamic containerized workloads. You explored how the feature maps Kubernetes attributes such as namespaces, pod names, cluster names, and labels to firewall rules, eliminating the need to track ephemeral IP addresses. You walked through how to create a container association to link your EKS cluster attributes to Network Firewall, and then how to reference that association using IP set references in Suricata compatible rule strings. This gives you granular traffic control of your Amazon EKS workloads with the same Network Firewall capabilities as traditional applications including layer 7 inspection, FQDN filtering, TLS decryption, and managed IDS/IPS rules along with enriched logging that traces traffic back to the originating workload.

If you have feedback about this post, submit comments in the Comments section below.

If you manage secrets across multiple AWS accounts or need faster secret access for latency-sensitive applications, this post shows you how to meet those requirements using two new features of the AWS Workload Credentials Provider (provider). You will learn how to configure role chaining for cross-account secret retrieval and prefetching of secrets to reduce cold-start latency.

By using role chaining, you can access secrets across AWS accounts through a single provider instance by assuming AWS Identity and Access Management (IAM) roles. Prefetching populates the provider’s in-memory cache with secrets at startup so your application can retrieve secrets without waiting for the first request to trigger a network call at runtime.

AWS Secrets Manager stores and rotates credentials, API keys, and other secrets. The AWS Workload Credentials Provider is a client-side HTTP service that retrieves and caches secrets locally. This reduces latency, improves availability during transient failures, and lowers costs. It supports post-quantum TLS by default, requires no language-specific SDK, and works across Amazon Elastic Compute Cloud (Amazon EC2), Amazon Elastic Container Service (Amazon ECS), Amazon Elastic Kubernetes Service (Amazon EKS), and AWS Lambda. For more details, see the Workload Credentials Provider documentation and GitHub repository.

The Server-Side Requst Forger (SSRF) token prevents unauthorized processes from accessing the provider’s HTTP endpoint. Only applications that can read the token file can retrieve secrets through the provider.

Any identity that can access the provider’s endpoint and SSRF token can retrieve secrets through role chaining. This means users with compute environment access can retrieve cross-account secrets when role assumption is configured. Scope the target role’s permissions to only the secrets required by following the principle of least privilege.

For prefetching, secrets are loaded into the provider’s in-memory cache at startup. Any process that can reach the provider’s localhost endpoint and provide a valid SSRF token can retrieve prefetched secrets from the cache.

Organizations might store secrets in a dedicated AWS account, or need to share one secret across applications in different accounts. Until now, cross-account retrieval through the provider required attaching resource-based policies directly to each secret. Some customers prefer IAM role assumption. Before this feature, you had to deploy multiple provider instances with different credentials or build custom credential-switching logic. The provider now supports both approaches: resource-based policies and IAM role assumption. While role assumption is especially useful for cross-account scenarios, it also helps within the same account when secrets are protected by different customer-managed KMS keys.

When you include the roleArn query parameter in a request, the provider uses AWS Security Token Service (AWS STS) AssumeRole to obtain temporary credentials for the specified role and retrieves the secret with those credentials. The provider creates and caches a separate client for each role ARN, so subsequent requests to the same role reuse the existing client. Each role client maintains its own independent cache.

Note: The source account runs the Workload Credentials Provider and your application. The target account contains the secret you want to retrieve. A single provider instance in the source account can assume roles in one or more target accounts.

• A Workload Credentials Provider built and installed in your environment (see the README for build instructions)
• AWS credentials configured in your compute environment with permission to call sts:AssumeRole on the target role ARN
  • If you also retrieve secrets from the source account through the provider, the credentials need secretsmanager:GetSecretValue and secretsmanager:DescribeSecret permissions for those secrets
• A secret in a target AWS account that you want to retrieve
• An IAM role in the target account with a trust policy that allows the provider’s identity to assume it

The provider is written in Rust and compiles to a single executable. The following steps are for an RPM-based system such as Amazon Linux 2023:

1. Install build dependencies:

   sudo yum -y groupinstall "Development Tools"

2. Install Rust:

   curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
   source "$HOME/.cargo/env"

3. Clone the repository and build the provider (use the latest tag available):

   git clone --branch <git tag> https://github.com/aws/aws-workload-credentials-provider.git
   cd aws-workload-credentials-provider
   cargo build --release

The compiled binary is at target/release/aws-workload-credentials-provider.

After building the provider, install it as a system service on your EC2 instance and configure access to the SSRF token.

1. After configuring your config.toml file (see Configuration options section), run the install script to deploy the provider as a systemd service and generate the SSRF token:

   cd aws_workload_credentials_provider_common/configuration
   sudo ./install --config config.toml

2. Add your application user to the aws-wcp-token group. This grants your application permission to read the SSRF token file, which is required for all secret retrieval requests:

   sudo usermod -aG aws-wcp-token <APP_USER>

To install on Amazon ECS, Amazon EKS, or Lambda, see the installation instructions in the GitHub repository.

1. Check that the provider is running:

   curl -v -H \
       "X-Aws-Parameters-Secrets-Token: $(</var/run/awssmatoken)" \
       'http://localhost:2773/secretsmanager/get?secretId=<YOUR_SECRET_ID>'

2. You’ll receive a JSON response with the secret value. If you see a connection refused error, check that the provider process is running. If you see a 401 or 403 error, verify the SSRF token file is readable and that the provider’s IAM credentials have secretsmanager:GetSecretValue and secretsmanager:DescribeSecret permissions.

The provider’s base IAM identity requires:

• sts:AssumeRole on the target role ARN

The target role requires:

• secretsmanager:GetSecretValue
• secretsmanager:DescribeSecret

Create an IAM role in the target account with a trust policy that allows the provider’s identity in the source account to assume it. Then attach a policy that grants access to the required secrets.

1. Create an IAM role in the target account with a trust policy that allows the provider’s identity in the source account to assume it.

   {
       "Version": "2012-10-17",
       "Statement": [
           {
               "Effect": "Allow",
               "Principal": {
                   "AWS": "arn:aws:iam::111111111111:role/WCProviderRole"
               },
               "Action": "sts:AssumeRole"
           }
       ]
   }
   

2. Attach a policy to this role that grants access to the secret:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "secretsmanager:GetSecretValue",
                "secretsmanager:DescribeSecret"
            ],
            "Resource": "arn:aws:secretsmanager:us-east-1:222222222222:secret:MyDatabaseSecret"
        }
    ]
}

Before the provider can assume the role you created in the target account, grant it permission to call sts:AssumeRole. Attach the following policy to the provider’s IAM role in the source account:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "sts:AssumeRole",
            "Resource": "arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole"
        }
    ]
}

Call the Workload Credentials Provider endpoint with the roleArn parameter. The following curl example shows how to retrieve a secret using a different IAM role:

curl -v -H "X-Aws-Parameters-Secrets-Token: $(</var/run/awssmatoken)" 'http://localhost:2773/secretsmanager/get?secretId=MyDatabaseSecret&roleArn=arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole'

The following Python example shows the same operation:

import requests

def get_secret_cross_account():
    role_arn = "arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole"
    url = f"http://localhost:2773/secretsmanager/get?secretId=MyDatabaseSecret&roleArn={role_arn}"

    with open('/var/run/awssmatoken') as fp:
        token = fp.read()

    headers = {
        "X-Aws-Parameters-Secrets-Token": token.strip()
    }

    response = requests.get(url, headers=headers)

    if response.status_code == 200:
        return response.text
    else:
        raise Exception(f"Status code {response.status_code} - {response.text}")

You can configure the maximum number of simultaneous assumed roles with the max_roles option in the provider’s TOML configuration file. The default is 20, and the range is 1–20.

By default, the Workload Credentials Provider populates its cache lazily—the first request for a secret triggers a network call to Secrets Manager. Prefetching reduces this cold-start latency by loading secrets at startup.

You can configure prefetching by adding a [capabilities.secrets_manager.prefetch] section to the provider’s TOML configuration file. You can specify secrets to prefetch in two ways:

• Explicit secrets – List specific secret IDs or ARNs using [[capabilities.secrets_manager.prefetch.secrets]] entries.
• Tag-based discovery – Discover secrets by tag key using [[capabilities.secrets_manager.prefetch.filter_tags]] entries. The provider calls BatchGetSecretValue with tag key filters to find and cache all matching secrets.

You can use both methods together. Each entry optionally accepts a role_arn field for cross-account prefetching through role chaining.

The following permissions are required on the IAM role that performs the prefetch, depending on whether the secrets are in the source account or a target account.

• secretsmanager:BatchGetSecretValue – Required on the source account role for source-account secrets, or on the target role for cross-account secrets
• secretsmanager:ListSecrets – Required when using tag-based discovery (filter_tags), on whichever role is performing the discovery

You can tune prefetch behavior with the following options in the [capabilities.secrets_manager.prefetch] section of your TOML configuration file:

• cache_buffer_ratio – The maximum fraction of the cache to fill per caching client during prefetch, in the range 0.1–1.0. The default is 0.8. For example, if your cache holds 100 secrets, a ratio of 0.8 prefetches up to 80, leaving room for 20 on-demand secrets to be cached.
• max_jitter_seconds – The maximum random delay in seconds before starting the prefetch task, in the range 0–10. The default is 0 (no jitter). Use this to prevent fleet-wide synchronized API calls when deploying across many instances.

The following configuration prefetches two secrets at startup, one from the source account and one from a different account using role chaining:

[capabilities.secrets_manager.prefetch]
secrets = [
    { secret_id = "arn:aws:secretsmanager:us-east-1:111111111111:secret:MySecret-AbCdEf" },
    { secret_id = "cross-account-secret", role_arn = "arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole" }
]

The following configuration discovers and caches all secrets tagged with the Environment key, and all secrets tagged with the Team key in a different account:

[capabilities.secrets_manager.prefetch]
filter_tags = [
    { key = "Environment" },
    { key = "Team", role_arn = "arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole" },
]

The following example shows a complete provider configuration that combines both features:

[logging]
log_level = "info"

[capabilities.secrets_manager]
http_port = 2773
region = "us-east-1"

[capabilities.secrets_manager.cache]
ttl_seconds = 300

[capabilities.secrets_manager.prefetch]
cache_buffer_ratio = 0.6
max_jitter_seconds = 5
secrets = [
    { secret_id = "arn:aws:secretsmanager:us-east-1:111111111111:secret:MySecret-AbCdEf" },
    { secret_id = "arn:aws:secretsmanager:us-east-1:222222222222:secret:CrossAccount-AbCdEf", role_arn = "arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole" },
]
filter_tags = [
    { key = "Environment" },
    { key = "Team", role_arn = "arn:aws:iam::222222222222:role/CrossAccountSecretAccessRole" },
]

Start the provider with your configuration file:

./aws-workload-credentials-provider sm start --config config.toml

This post showed you how to use role chaining for cross-account secret retrieval and prefetching to reduce cold-start latency. Role chaining simplifies multi-account architectures—a single provider instance can retrieve secrets across accounts using IAM role assumption. Prefetching reduces cold-start latency by populating the provider’s cache before your application makes its first request. Combined, these features let you run the Workload Credentials Provider across multiple accounts with faster secret access.

• AWS Workload Credentials Provider documentation
• Access AWS Secrets Manager secrets from a different account
• GitHub repository for source code and README
• AWS Secrets Manager documentation

Submit feedback in the comments below, or contact AWS Support with questions.

Amazon Web Services (AWS) recently announced support for resource-based policies and resource control policies (RCPs) for AWS Sign-In. By using resource-based policies and RCPs, you can restrict access to the AWS Management Console sign-in and aws login CLI sessions to requests from your expected networks, your on-premises data center networks, and your Amazon Virtual Private Cloud (Amazon VPC) VPCs.

Sign-in resource-based policies and RCPs support several security objectives: restricting console sign-in to corporate networks, limiting which principals can sign-in to the console, and applying consistent network perimeter controls across an entire AWS Organizations organization.

In this post, we walk through a common use case: a financial services company restricting console access to its corporate network for regulatory compliance. We show you how to implement this using a sign-in resource-based policy for a single account, verify the controls with AWS CloudTrail, and explain how these policies integrate with AWS Management Console Private Access and the broader AWS data perimeter framework.

Consider a financial services company that requires access to AWS Management Console sign-in to originate from the corporate network. The company has the following requirements:

• Users sign in to the console only from the corporate VPN, office network, or customer VPC.
• Sign-in attempts from personal networks, public Wi-Fi, or other unexpected locations must be denied.
• A designated principal should retain access from any network to prevent lockout.
• All sign-in attempts (allowed and denied) must be logged to CloudTrail for compliance evidence.

In the steps that follow, we show you how to create a resource-based policy to enforce these requirements on a single account.

• AWS Command Line Interface (AWS CLI) installed and configured with the latest version.
• Permission to manage Sign-in resource policies. Attach the AWS managed policy AWSSignInResourcePolicyManagement or grant permissions to the following actions to respective principals:
  • Manage resource permission statements: signin:PutResourcePermissionStatement, signin:DeleteResourcePermissionStatement, signin:ListResourcePermissionStatements, signin:GetResourcePolicy.
  • Manage console authorization: signin:PutConsoleAuthorizationConfiguration, signin:GetConsoleAuthorizationConfiguration, signin:DeleteConsoleAuthorizationConfiguration
• Identified corporate network: IP CIDR range or VPC ID.
• Designated principal Amazon Resource Name (ARN) to exclude, so it retains access if network conditions change.

Note: For the complete list of AWS Sign-In actions see Actions, resources, and condition keys for AWS Sign-In in the Service Authorization Reference.

Most resource-based policies require the author to input the full policy document (JSON statements). A Sign-in resource permission statement is different: you provide parameters, and AWS Sign-In generates the policy for you.

The following command provides your corporate IP range, your VPC, and an excluded principal as parameters. AWS Sign-In uses these parameters to generate a policy that restricts console sign-in to those networks, while letting the excluded principal sign in from any network. You control the parameter values, not the policy structure. You can review the generated policy at any time with the get-resource-policy command.

Note: Creating resource permission statements has no effect until console authorization is enabled in Step 2, so you can review the complete policy before it takes effect. Write operations must target us-east-1.

To create resource permission statements

1. Open your terminal and ensure you have the latest AWS CLI installed.
2. Run the following command, replacing the placeholder values <my-vpc>, <my-vpc-region>, <my-corporate-cidr>, and <excluded-IAM-principal-arn> with your specific configuration:

aws signin put-resource-permission-statement \
  --source-vpc <my-vpc> \
  --requested-region <my-vpc-region> \
  --source-ip <my-corporate-cidr> \
  --excluded-principal <excluded-IAM-principal-arn> \
  --region us-east-1

3. Verify the command succeeded by checking for a statementId in the output.

Example output:
{
“statementId":"b2HfHli9qCF1P4eGNll13CrZtusXlcPxxVBqz2aYLjlAcWtWQHP6Hg0"
}

4. Review the complete resource-based policy by running get-resource-policy command.

aws signin get-resource-policy

Example output:

{
  "signinResourceBasedPolicy": {
    "Version": "2012-10-17",
    "Statement": [
      {
        "Effect": "DENY",
        "Principal": {"AWS": "*"},
        "Action": ["signin:Authenticate"],
        "Resource": "*",
        "Condition": {
          "ArnNotEquals": {"signin:PrincipalArn": ["<excluded-IAM-principal-arn>"]},
          "NotIpAddress": {"aws:SourceIp": ["<my-corporate-cidr>"]},
          "StringEquals": {"aws:ResourceAccount": ["<account-id>"]},
          "StringNotEquals": {"aws:SourceVpc": ["<my-vpc>"]}
        }
      },
      {
        "Effect": "DENY",
        "Principal": {"AWS": "*"},
        "Action": ["signin:CreateOAuth2Token", "signin:AuthorizeOAuth2Access"],
        "Resource": "*",
        "Condition": {
          "ArnNotEquals": {"aws:PrincipalArn": ["<excluded-IAM-principal-arn>"]},
          "NotIpAddress": {"aws:SourceIp": ["<my-corporate-cidr>"]},
          "StringEquals": {"aws:ResourceAccount": ["<account-id>"]},
          "StringNotEquals": {"aws:SourceVpc": ["<my-vpc>"]}
        }
      },
      {
        "Effect": "DENY",
        "Principal": {"AWS": "*"},
        "Action": ["signin:Authenticate"],
        "Resource": "*",
        "Condition": {
          "ArnNotEquals": {"signin:PrincipalArn": ["<excluded-IAM-principal-arn>"]},
          "StringEquals": {"aws:SourceVpc": ["<my-vpc>"]},
          "StringNotEquals": {"aws:RequestedRegion": ["<my-vpc-region>"]}
        }
      },
      {
        "Effect": "DENY",
        "Principal": {"AWS": "*"},
        "Action": ["signin:CreateOAuth2Token", "signin:AuthorizeOAuth2Access"],
        "Resource": "*",
        "Condition": {
          "ArnNotEquals": {"aws:PrincipalArn": ["<excluded-IAM-principal-arn>"]},
          "StringEquals": {"aws:SourceVpc": ["<my-vpc>"]},
          "StringNotEquals": {"aws:RequestedRegion": ["<my-vpc-region>"]}
        }
      }
    ]
  }
}

The generated policy contains four statements, grouped into two pairs. The first pair restricts access by network source—it denies any principal making a request from outside your corporate IP range (<my-corporate-cidr>) or your VPC (<my-vpc>). The second pair restricts which AWS Region your VPC can target—it denies requests originating from <my-vpc> unless they are directed at <my-vpc-region>. This Region binding is necessary because VPC IDs are only unique within a single Region.

AWS Sign-In evaluates these policies in two phases: before authentication and after authentication. The post-authentication evaluation repeats each time the console session requests new credentials. Within each pair, one statement covers the pre-authentication phase and one covers the post-authentication phase.

The pre-authentication statement evaluates the signin:Authenticate action. Since the principal is not yet authenticated in this phase, the statement uses the signin:PrincipalArn condition key to exempt your excluded principal. This key supports all principal types: root user, AWS Identity and Access Management (IAM) user, federated user, and role.

The post-authentication statement evaluates the signin:AuthorizeOAuth2Access and signin:CreateOAuth2Token actions. AWS Sign-In evaluates these actions after authentication, when it issues the tokens that establish the console session. These actions do not support the signin:PrincipalArn key. Instead, they use aws:PrincipalArn, which resolves to the authenticated principal.

The aws:ResourceAccount value is the recipient account ID. AWS Sign-In pulls it automatically from your caller credentials, so you do not set it yourself. For the full list of supported actions and condition keys, including which keys apply at each phase and to each principal type, see Controlling console access with resource-based policies and resource control policies and AWS Sign-In condition keys reference.

This step turns on enforcement of the policy you created in Step 1. Until you run this step, the resource permission statements you created in Step 1 have no effect.

5. Turn on enforcement of sign-in policies using the following command:

aws signin put-console-authorization-configuration \
  --target-id <account-id> \
  --region us-east-1

6. Verify the command succeeded by checking for a “consoleAuthorizationEnabled": true in the output.

Example output:

{
“Output": {
“consoleAuthorizationEnabled": true,
“scope": “ACCOUNT”,
“targetId": "<account-id>"
}
}

7. You can also verify the configuration by executing the get-console-authorization-configuration command as shown below:

aws signin get-console-authorization-configuration \
  --target-id <account-id> \
  --region us-east-1

8. To disable enforcement or remove individual statements, use delete-console-authorization-configuration or delete-resource-permission-statement. For more details, see Controlling console access with resource-based policies and resource control policies in the AWS Sign-In User Guide.

Now that enforcement is active, sign-in attempts are evaluated against your resource-based policy. Verify the behavior by testing sign-in from different network conditions.

A principal signing in from the allowed corporate IP range or VPC succeeds normally. The CloudTrail event shows ConsoleLogin:Success

Example CloudTrail event details for successful console sign-in:

{
    "userIdentity": {
        "type": "AssumedRole",
        "principalId": "AROAEXAMPLEID:Dev1",
        "arn": "arn:aws:sts::123456789123:assumed-role/Developer/Dev1",
        "accountId": "123456789123"
    },
    "eventTime": "2026-06-09T19:20:38Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "ConsoleLogin",
    "awsRegion": "us-east-1",
    "sourceIPAddress": "192.0.2.100",
    "responseElements": {
        "ConsoleLogin": "Success"
    },
    "eventID": "dd004e78-6447-4f56-8d2d-a795da66f598",
    "readOnly": false,
    "eventType": "AwsConsoleSignIn",
    "managementEvent": true,
    "recipientAccountId": "123456789123",
    "eventCategory": "Management"
}

A principal signing in from a network other than the allowed IP address range or a VPC endpoint attached to the source VPC, is blocked. The CloudTrail event shows ConsoleLogin: Failure with an error message identifying the policy that caused the denial:

Example CloudTrail event details for failed console sign-in:

{    
"userIdentity": {
    "type": "IAMUser",
    "accountId": "123456789123",
    "accessKeyId": "",
    "userName": "Dev1"
    },
    "eventTime": "2026-06-09T19:20:38Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "ConsoleLogin",
    "awsRegion": "us-east-1",
    "sourceIPAddress": "198.51.100.76",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36",
    "errorCode": "AccessDenied",
    "errorMessage": "Authorization denied because of a resource-based policy",
    "requestParameters": null,
    "responseElements": {
        "ConsoleLogin": "Failure"
    },
"eventID": "d88a7543-ae89-4186-b1b6-d3116413f2ee",
"readOnly": false,
"eventType": "AwsConsoleSignIn",
"managementEvent": true,
"recipientAccountId": "123456789123",
"eventCategory": "Management"
}

The error message field shows the policy type that caused the denial: “Authorization denied because of a resource-based policy”.

The steps above apply a Sign-in resource-based policy to a single account. For organizations managing many accounts, RCPs offer a better path: they can be attached at the organization, OU, or account level in AWS Organizations and apply automatically to every account in scope. To view an RCP example, see here .

When a sign-in to the console is denied because of an RCP, the error message field shows the denial as “Authorization denied because of a resource control policy”.

The sign-in resource-based policy you created controls which networks can reach your account’s sign-in flow. AWS Management Console Private Access adds a complementary control: from within your network, it limits console access to a known set of AWS accounts, preventing sign-in to unexpected AWS accounts.

Together, these capabilities contribute to a data perimeter for console access:

• Network perimeter: Sign-in resource-based policies and RCPs restrict console sign-in to expected networks (corporate IP ranges, VPCs).
• Identity perimeter: Sign-in resource-based policy and RCP ensure only trusted identities can sign in to the console. Console VPC endpoint policy and Sign-in VPC endpoint policy ensure only trusted identities can use the console from your VPC.
• Resource perimeter: Sign-in VPC endpoint policy and Console VPC endpoint policy restrict which AWS accounts are reachable from your network.

The controls in this post focus on console access. To extend these perimeters to other AWS services and broader implementation scenarios, see the Data perimeter policy examples repository and the Data Perimeters Blog Post Series.

By using sign-in resource-based policies and RCPs, you can restrict AWS Management Console access to expected networks. These controls are available at no additional cost in all AWS commercial Regions.

To get started, see the AWS Sign-in User Guide. For organization-wide enforcement, see Resource control policies in the AWS Organizations User Guide.

If you have feedback about this post, submit comments in the Comments section below.

When securing an Amazon Web Services (AWS) environment, teams naturally prioritize inbound controls, firewalls, WAFs, and access policies, because that’s where the most visible threats originate. Outbound traffic, on the other hand, tends to get less attention. It’s often left open by default to avoid breaking application dependencies and because the risk feels less immediate. But overlooking egress means missing a key layer of defense. Without visibility into what’s leaving your network, it’s harder to detect unintended data flows, whether from misconfigured services, overly broad permissions, or workloads with unauthorized access.

Real-world incidents highlight why egress controls deserve attention across both traditional cloud workloads and emerging AI-driven architectures.

In traditional cloud environments, application-level security issues remain a persistent threat. For example, when CVE-2025-55182 (React2Shell) was publicly disclosed in December 2025, multiple organized groups began exploitation attempts within hours, targeting unpatched React Server Components to achieve remote code execution. After a workload is accessed by an unauthorized party, they typically establish outbound command-and-control channels and begin exfiltrating data. Without egress controls in place, that outbound traffic can flow freely, and the unauthorized access might go unnoticed until a compliance audit, customer complaint, or incident notification forces discovery.

Agentic AI systems introduce a new dimension to this risk. The OWASP Top 10 for Agentic Applications identifies threats such as Agent Goal Hijack (ASI01), where unauthorized parties manipulate an autonomous agent’s objectives to silently exfiltrate data, and Unexpected Code Execution (ASI05), where an agent with unauthorized access generates and runs potentially damaging code that establishes reverse shells or transfers sensitive data to external endpoints. As organizations deploy AI agents with access to tools, APIs, and code interpreters, these agents become high-value targets, and their outbound network activity must be constrained with the same rigor as any other workload.

In both scenarios, the common thread is unauthorized outbound traffic. In this post, we show you how to implement layered egress detection and protection using AWS services working together to reduce unauthorized data transfer risk, whether the source is an application with unauthorized access or a manipulated AI agent.

Architecture overview

Figure 1: Hub-and-spoke egress control architecture

The following architecture, shown in Figure 1, illustrates one approach to implementing a hub-and-spoke network pattern for a multi-account AWS environment. Note that alternative designs might be appropriate depending on your organizational requirements and constraints.

Application workloads reside in spoke virtual private clouds (VPCs) that connect to an AWS Transit Gateway, which serves as the central hub for routing inter-VPC and internet-bound traffic while enforcing network segmentation through carefully crafted route tables. Spoke VPCs use VPC endpoints for secure AWS service access, keeping traffic within the AWS network where possible. VPC endpoint policies are applied as key data perimeter controls, restricting which principals can access AWS services and which resources can be accessed through these endpoints.

Internet-bound traffic is routed through a transit gateway-attached AWS Network Firewall, which inspects and filters outbound flows before they reach the internet. This centralized routing model scales horizontally by adding spoke VPCs without modifying the inspection infrastructure, making it well suited for organizations that have multiple AWS accounts.

It’s important to understand that Amazon Route 53 Resolver DNS Firewall must be deployed across your VPCs to filter DNS queries that resolve through the Route 53 VPC Resolver. (DNS queries sent directly to other DNS resolvers bypass it, but can be filtered with AWS Network Firewall.) The DNS firewall uses both managed and custom domain lists to filter DNS queries, blocking resolution of known unauthorized domains before any network connection is established.

Data perimeter controls are enforced at multiple layers: service control policies (SCPs) and resource control policies (RCPs) at the AWS Organizations level, VPC endpoint policies at the network level, and resource policies on individual services. AWS IAM Access Analyzer is deployed at the organization level to continuously detect publicly accessible or externally shared resources.

A detection layer comprising Amazon GuardDuty, AWS Security Hub, and IAM Access Analyzer provides continuous monitoring and threat detection. Findings are routed through an integration layer using Amazon EventBridge, which triggers AWS Lambda-based automated remediation and sends notifications using Amazon Simple Notification Service (Amazon SNS). This integration layer also feeds back into your network controls, automatically updating Network Firewall deny rules and DNS Firewall block lists based on detected threats.

Centralized observability is achieved through Amazon CloudWatch Logs and CloudWatch dashboards. Network Firewall flow logs and alert logs are collected centrally to support incident investigation and compliance reporting.

This architecture applies equally to traditional application workloads and AI-driven workloads. An AI agent running on Amazon Bedrock, for example, typically sits inside a spoke VPC. When that agent invokes an external API or attempts to reach the internet, its traffic follows the same path through Transit Gateway and Network Firewall as any Amazon Elastic Compute Cloud (Amazon EC2) or container workload. The agent doesn’t get a special lane out, it’s subject to the same domain allow-lists, the same DNS filtering, and the same data perimeter policies.

That said, agents often need outbound access to invoke external tools or third-party APIs as part of their normal operation, which makes allow-list design more nuanced. You will want to scope allowing domains tightly to the specific endpoints your agents legitimately need, rather than opening broad categories. Complementing these network-layer controls with application-layer guardrails such as Amazon Bedrock Guardrails—which can filter harmful content and detect prompt attacks before they reach the network layer—adds another layer of defense.

Preventive controls

The following preventive controls block data exfiltration before it occurs. Because they actively disrupt traffic, reserve them for activity that is confirmed or highly likely to be potentially damaging.

AWS Network Firewall

Consider this scenario: an unauthorized party compromises an EC2 instance in one of your spoke VPCs and attempts to exfiltrate sensitive data to an external server. Now consider an agentic AI scenario: an unauthorized party uses prompt injection to hijack an AI agent’s goal (OWASP ASI01), redirecting it to exfiltrate training data to an external endpoint. Network Firewall is designed to block this attempt because the unauthorized destination isn’t on the approved domain allow-list—the same control that stops an EC2 instance with unauthorized access— also stops a manipulated AI agent.

Without centralized egress inspection, that traffic flows directly to the internet through a NAT gateway. Network Firewall prevents this by providing centralized, Layers 3–7 deep packet inspection with advanced threat intelligence capabilities, including IP address, port, and protocol filtering; plus packet content inspection using Suricata-compatible rules.

In this architecture, Transit Gateway funnels internet-bound traffic from multiple spoke VPCs through Network Firewall for centralized inspection. The firewall endpoint becomes the target for 0.0.0.0/0 routes, routing outbound internet traffic for inspection before reaching NAT gateways for address translation. In both scenarios, Network Firewall blocks the exfiltration attempt at the network layer before data leaves your environment. Its key capabilities include:

• Domain name filtering: Block traffic to unauthorized destinations (such as a command-and-control server at *.untrusted-domain.com)
• IP and port rules: Define explicit allow-lists for external IPs your applications truly need, blocking everything else
• Domain category filtering: Block entire categories of domains that your workloads should never communicate with
• IDS and IPS: Detect and block known attack patterns in outbound traffic using Suricata-compatible rules
• Port and protocol enforcement: Help ensure only expected protocols use their designated ports (for example, only HTTPS on TCP port 443), preventing protocol tunneling
• Geographic IP filtering: Block outbound traffic to geographic regions where your organization has no business relationships
• TLS decryption: Inspect encrypted traffic to detect exfiltration attempts hidden within HTTPS connections
• Threat intelligence integration: Use managed threat intelligence (such as active threat defense that uses the Amazon threat intelligence system MadPot) feeds or custom Suricata rules to detect unexpected patterns
• Automatic scaling: Handles up to 100 Gbps per Availability Zone

For multi-account environments, AWS Firewall Manager can centrally deploy and manage Network Firewall across your organization’s accounts, helping maintain consistent egress rules everywhere. Additionally, AWS Network Firewall Proxy (in preview) offers explicit proxy capabilities with granular HTTP/HTTPS filtering—including URL path and HTTP method-level controls—for workloads that require application-layer inspection of outbound web traffic.

Route 53 Resolver DNS Firewall

DNS queries made through Route 53 VPC Resolver don’t pass through the outbound network path inspected by Network Firewall or third-party firewalls. Unauthorized parties can take advantage of this by encoding sensitive data within DNS queries to external servers, a technique known as DNS tunneling. This risk extends to agentic AI workloads. An agent with code execution capabilities (OWASP ASI05) could be tricked into running a script that encodes sensitive data (like customer records, model weights, API keys) into DNS queries directed at an externally controlled nameserver. DNS Firewall is designed to block these queries regardless of whether they originate from a traditional workload or an AI agent, because the filtering happens at the resolver level before any connection is established.

Because DNS traffic is essential for normal operations and often overlooked in security architectures, it represents a common unauthorized data exfiltration channel. Route 53 Resolver DNS Firewall closes this gap by filtering and potentially blocking outbound DNS queries from your VPCs. Its core capabilities consist of:

• Block unauthorized domains: AWS provides managed domain lists, including an Aggregate Threat List covering malware, ransomware, botnet, spyware, and DNS tunneling
• Enforce allow-lists: Permit only queries to approved domains, blocking everything else
• DNS Firewall Advanced features: AI and machine learning (AI/ML)-backed detection of DNS tunneling, Domain Generation Algorithms (DGAs), and dictionary DGAs

Configuration is straightforward: Create rule groups with domain match lists and actions (block, allow, and alert), then associate them with your VPCs. The DNS resolver applies these rules to every DNS query made from instances in the VPC through Route 53 Resolver. This prevents unauthorized parties from using DNS tunneling to exfiltrate data, a technique that completely bypasses inspection by firewalls in the egress VPC.

For a deeper look at the risks associated with DNS exfiltration and DNS Firewall Advanced capabilities, see Protect against advanced DNS threats with Amazon Route 53 Resolver DNS Firewall.

Data perimeters

A data perimeter is a set of preventive guardrails that allow only your trusted identities to access trusted resources from expected networks. While the preceding controls secure the network paths out of your environment, data perimeters secure the API-level paths, helping to ensure that even if an unauthorized party gains access to valid credentials, they can’t use AWS service APIs to move data to resources outside your organization.

This comprehensive approach uses three primary AWS capabilities working together:

1. Service control policies (SCPs): Organization-wide preventive controls that restrict what identities can do. In the context of egress protection, SCPs can prevent users from creating resources that bypass your egress controls (for example, preventing the creation of VPCs without DNS Firewall associations or blocking the use of services that could establish alternative outbound paths).
2. Resource control policies (RCPs): Controls that restrict API access to your resources. While RCPs aren’t directly egress controls, they act as a complementary layer. For example, they can block attempts to access your Amazon Simple Storage Service (Amazon S3) buckets from outside your organization at the resource level.
3. VPC endpoint policies: VPC endpoints enable private communication with AWS services without traffic going through the internet. VPC endpoint policies are resource-based AWS Identity and Access Management (IAM) policies that govern what can be accessed through that endpoint. This is where data perimeters most directly function as an egress control.

Consider the following VPC endpoint policy that restricts Amazon S3 access through the endpoint to only S3 buckets within your organization, directly preventing an insider or a workload with unauthorized access from copying data to an external S3 bucket:

{
  "Statement": [{
    "Sid": "DenyAccessToNonOrgBuckets",
    "Effect": "Deny",
    "Principal": "*",
    "Action": "s3:*",
    "Resource": "*",
    "Condition": {
      "StringNotEqualsIfExists": {
        "aws:ResourceOrgID": "<my-org-id>"
      }
    }
  }]
}

This policy is designed to deny any Amazon S3 operation through this VPC endpoint unless the target S3 bucket belongs to your organization. Without this control, a workload with unauthorized access could use aws s3 cp to copy sensitive data to an externally controlled bucket in a different AWS account.

Data perimeter policies don’t grant new permissions, they narrow what’s accessible by establishing guardrails, acting as a second authorization layer. By implementing these perimeters using IAM condition keys like aws:PrincipalOrgID, aws:ResourceOrgID, aws:SourceVpc, and aws:SourceVpce, you create layered permissions guardrails that help prevent unintended access patterns and configuration errors.

For more information on implementing perimeter controls, explore the Building a Data Perimeter AWS whitepaper.

Detective controls

The following detective controls surface data exfiltration attempts after they occur. Because they observe rather than disrupt traffic, you can apply them broadly to flag unexpected activity for investigation. Use the findings to identify recurring unauthorized patterns that can graduate into preventive controls.

Amazon GuardDuty: Detective control for egress threats

GuardDuty serves as your critical detection layer for egress protection, continuously monitoring for outbound threats that evade or take advantage of your preventive controls. GuardDuty identifies behavioral anomalies and attack patterns that indicate active data exfiltration attempts. Its egress-focused detection capabilities include:

• DNS-based data exfiltration detection: The Trojan:EC2/DNSDataExfiltration finding alerts when EC2 instances are transferring data through DNS channels. GuardDuty also identifies queries to DGA domains commonly used for command-and-control communication.
• Known malicious actor detection: Exfiltration:S3/MaliciousIPCaller triggers when Amazon S3 data APIs like GetObject or CopyObject are invoked from IP addresses on AWS threat intelligence feeds, signaling active data extraction attempts.
• Multi-step attack sequence correlation: GuardDuty Extended Threat Detection correlates multiple unexpected events to identify multi-stage exfiltration campaigns. For example, AttackSequence: S3/CompromisedData detects when unauthorized parties modify S3 bucket policies to broaden access and then systematically extract data using stolen credentials.

GuardDuty findings serve dual purposes in your egress strategy. Alerts about attempted exfiltration that failed confirm your preventive layers (Network Firewall, DNS Firewall, and data perimeters) are functioning effectively: the threat was detected because it progressed far enough to trigger behavioral analysis, but your controls blocked the actual data loss. Conversely, findings indicating successful exfiltration trigger immediate incident response workflows, enabling you to contain active incidents, revoke stolen credentials, and quarantine affected resources before significant damage occurs.

Integrate GuardDuty with Security Hub for centralized correlation across your security services and implement automated response through EventBridge and Lambda functions to enable real-time containment when high-severity exfiltration findings occur.

IAM Access Analyzer

IAM Access Analyzer helps identify potential data exfiltration paths by detecting resources accessible from outside your AWS account or organization. It uses automated reasoning technology to analyze resource-based policies and identify which of your resources can be accessed by external entities (principals outside your zone of trust), continuously monitoring public and cross-account access.

External access analyzers identify resources shared with external principals (such as other AWS accounts or public access). For example, when an S3 bucket is configured to allow access outside your zone of trust through bucket policies, ACLs, or access points, IAM Access Analyzer generates a finding with details about the access path, including the external principal and the level of access granted. Security teams can respond by taking immediate action to remove unintended access or by setting up automated notifications through EventBridge to engage development teams for remediation.

AWS Security Hub

Security Hub exposure findings provide a comprehensive view of potential security risks by correlating data from multiple AWS security services. These findings identify when resources might be vulnerable to data exfiltration by integrating intelligence from GuardDuty (for threat detection), Amazon Inspector (for vulnerability assessment), Security Hub CSPM (for configuration compliance), and Amazon Macie (for sensitive data discovery). For example, it can identify when a publicly exposed S3 bucket contains sensitive data and isn’t encrypted at rest, flagging it as a potential data exfiltration risk that requires immediate attention.

AWS Shield network security director (in preview) complements Security Hub by discovering and analyzing your network topology to identify resources with unrestricted outbound internet access, helping you detect potential egress blind spots across your environment.

Egress security strategy

You don’t need to implement all these controls at once. The following phased approach lets you build your egress security posture incrementally, at a pace that matches your organization’s operational maturity and risk tolerance.

• Phase 1 – Quick wins: Enable Route 53 DNS Firewall across your VPCs to close the DNS exfiltration gap. Enable GuardDuty across your accounts for baseline threat detection.
• Phase 2 – Foundational: Deploy organization-wide data perimeters (SCPs, RCPs, and VPC endpoint policies). Deploy Network Firewall as a transit gateway-attached firewall.
• Phase 3 – Efficient: Enable IAM Access Analyzer for continuous external access detection. Implement automated remediation through EventBridge and Lambda to update firewall rules in real time. Centralize findings in Security Hub with automated alerting.

Conclusion

Egress security isn’t a single control—it’s a layered strategy. Start by assessing your current posture across network filtering, DNS security, data perimeters, and detective controls. Identify the gaps, then follow the phased approach outlined in this post to close them incrementally. Regular testing through simulated exfiltration attempts validates that your controls work effectively. These controls apply with equal force to agentic AI workloads, where manipulated agents can become unintended exfiltration vectors. Put egress under control and turn your outbound blind spots into monitored checkpoints.

If you have feedback about this post, submit comments in the Comments section below.