Api Key Exposure in Spring Boot with Dynamodb

Spring Boot applications that interact with Amazon DynamoDB typically rely on an AWS SDK client configured with credentials. If those credentials are handled insecurely, an attacker can retrieve API keys and use them to access or modify DynamoDB resources. Common causes include storing long-term access keys in source code or configuration files, logging credential material, or passing keys through query parameters or HTTP headers that are not adequately protected in transit or at rest.

When an API key is exposed, the attacker can perform actions with the associated IAM permissions. For DynamoDB, this may include reading or writing sensitive tables, increasing read/write capacity costs, or deleting data. Because DynamoDB is often used to store application state or user data, compromised keys can lead to significant confidentiality and integrity impacts. The risk is compounded when the exposed key has broad permissions, such as dynamodb:*, and when the application does not enforce additional authorization checks on individual requests.

In a black-box scan, middleBrick tests for unauthenticated endpoints that may leak credentials and checks whether API keys are inadvertently returned in responses or logs. The scanner also examines OpenAPI specifications and runtime behavior for indicators of missing authorization on sensitive operations, such as fetching or updating DynamoDB streams or performing administrative actions. Findings related to API key exposure highlight insecure handling of secrets rather than protocol weaknesses, emphasizing the need to separate credentials from application code and to apply the principle of least privilege.

An attacker who obtains an API key might probe the exposed DynamoDB endpoints to enumerate table names, read items with sensitive attributes, or inject malicious update expressions. Because DynamoDB requests are typically signed with the leaked key, any signed requests that reach the service will be accepted if the key remains valid. This is why detection of key exposure is critical before an attacker can leverage it for data exfiltration or privilege escalation within your AWS environment.

To reduce the risk of API key exposure, move credentials out of code and configuration files, and use short-lived tokens provided by an identity provider or AWS security token service. In Spring Boot, you can configure the AWS SDK to source credentials from environment variables or instance metadata, and you can enforce authorization checks in your service layer before invoking DynamoDB operations.

Use Spring’s configuration to rely on the default credential provider chain, which checks environment variables, system properties, and local instance credentials in a secure order. Avoid defining access keys as plain strings in application.properties or application.yml.

// Secure AWS configuration in Spring Boot
@Configuration
public class AwsConfig {

    @Bean
    public DynamoDbClient dynamoDbClient() {
        return DynamoDbClient.builder()
                .region(Region.US_EAST_1)
                .build();
    }
}

When calling DynamoDB, ensure that each request is authorized by your application logic. Do not rely on the IAM policy attached to the credentials alone; validate ownership or permissions within your service code. For example, when retrieving an item by user ID, include the user identifier in the key condition and confirm that the requester matches that identifier.

// Secure DynamoDB get item with user context check in Spring Boot
@Service
public class UserProfileService {

    private final DynamoDbClient dynamoDbClient;
    private final UserContext userContext; // contains current user ID

    public UserProfileService(DynamoDbClient dynamoDbClient, UserContext userContext) {
        this.dynamoDbClient = dynamoDbClient;
        this.userContext = userContext;
    }

    public GetItemResponse getItem(String tableName, String itemId) {
        String userId = userContext.currentUserId();
        Map key = Map.of(
                "userId", AttributeValue.builder().s(userId).build(),
                "itemId", AttributeValue.builder().s(itemId).build()
        );
        GetItemRequest request = GetItemRequest.builder()
                .tableName(tableName)
                .key(key)
                .build();
        return dynamoDbClient.getItem(request);
    }
}

Rotate keys regularly and use AWS IAM policies that limit actions and resources. Enable CloudTrail logging to detect unusual API activity, and consider using DynamoDB encryption at rest with customer-managed keys to add another layer of protection. With these practices, even if an API key is exposed, the blast radius is reduced and detection is faster.

middleBrick’s scans can identify endpoints that may leak credentials and highlight missing authorization checks on DynamoDB-related operations. By integrating the GitHub Action, you can add API security checks to your CI/CD pipeline and fail builds if risk scores drop below your defined threshold. The MCP Server allows you to scan APIs directly from your AI coding assistant, helping catch insecure patterns early during development.