Missing Tls in Buffalo with Dynamodb

When a Buffalo application communicates with Amazon DynamoDB without enforcing Transport Layer Security (TLS), credentials, session tokens, and query payloads can traverse the network in cleartext. This is a TLS configuration oversight at the client level, not a DynamoDB server-side weakness: DynamoDB supports HTTPS endpoints, but if the client omits TLS verification or uses plain HTTP, the confidentiality and integrity guarantees of the data in transit are lost.

In a typical Buffalo app written in Go, developers may initialize an AWS SDK session without explicitly enforcing TLS or without validating server certificates. For example, using the default AWS SDK configuration with an HTTP client that does not require TLS can allow connections to a man-in-the-middle (MITM) on a compromised network to intercept requests to DynamoDB. Attackers can capture AWS access keys embedded in requests, alter queries, or inject malicious commands. Because the application trusts the connection without verifying the server identity, the unauthenticated attack surface expands: an attacker on the same network or via a rogue access point can observe sensitive operations such as GetItem or BatchGetItem that may reveal business logic or data classification.

Additionally, Buffalo applications that generate presigned URLs for DynamoDB objects (e.g., for uploads or downloads) may produce HTTP URLs instead of HTTPS when constructing the client configuration. If middleware does not enforce secure URL generation, downstream clients receiving these presigned URLs will use cleartext connections, exposing object keys and any embedded metadata. This scenario is especially risky when combined with weak CORS or bucket policies, as the exposure of presigned URLs over HTTP can lead to unauthorized access or tampering.

The interaction with DynamoDB’s region endpoints and custom endpoint configurations can exacerbate the issue. If the Buffalo app overrides the default AWS endpoint with a non-TLS address or fails to pin certificates, requests may inadvertently route through unencrypted channels. Because DynamoDB does not redirect HTTP to HTTPS, the client must ensure TLS is used explicitly. The scanner checks for these client-side misconfigurations as part of unauthenticated black-box testing, flagging missing TLS enforcement in API calls that handle sensitive operations.

Remediation centers on ensuring all DynamoDB interactions in Buffalo enforce TLS with proper certificate validation. In Go, this is typically achieved by configuring the AWS SDK HTTP client to use tls.Config with secure defaults and avoiding custom transports that disable verification.

First, initialize the DynamoDB client with a custom HTTP client that requires TLS and verifies server certificates:

// Example: Secure DynamoDB client in Buffalo
awsCfg, err := config.LoadDefaultConfig(context.TODO(),
    config.WithRegion("us-west-2"),
    config.WithHTTPClient(&http.Client{
        Transport: &http.Transport{
            TLSClientConfig: &tls.Config{
                MinVersion: tls.VersionTLS12,
            },
        },
    }),
)
if err != nil {
    // handle error
}
svc := dynamodb.NewFromConfig(awsCfg)

This ensures that every request to DynamoDB uses TLS 1.2 or higher and validates server certificates. Avoid setting InsecureSkipVerify to true, as that would defeat the purpose of TLS verification.

Second, when generating presigned URLs for DynamoDB operations (e.g., for S3 object access triggered from DynamoDB metadata), explicitly enforce HTTPS:

// Generate HTTPS presigned URLs for secure sharing
presigner := dynamodb.NewPresignClient(svc)
result, err := presigner.PresignGetItem(context.TODO(), &dynamodb.GetItemInput{
    TableName: aws.String("widgets"),
    Key: map[string]types.AttributeValue{
        "id": &types.AttributeValueMemberS{Value: "123"},
    },
}, func(opts *presign.PresignOptions) {
    opts.Expires = 15 * time.Minute
})
if err != nil {
    // handle error
}
// Ensure the URL uses HTTPS
if !strings.HasPrefix(result.URL, "https://") {
    // reject or rewrite to HTTPS
}

Third, validate endpoint configurations to prevent accidental use of non-TLS endpoints. If the application uses custom endpoints (e.g., for DynamoDB Local in development), ensure they are only used in trusted environments and that TLS is still enforced when applicable:

// Custom endpoint example with TLS enforcement
awsCfg, err := config.LoadDefaultConfig(context.TODO(),
    config.WithEndpointResolverWithOptions(aws.EndpointResolverWithOptionsFunc(
        func(service, region string, options ...interface{}) (aws.Endpoint, error) {
            return aws.Endpoint{
                URL:           "https://localhost:8000", // enforce HTTPS even for local testing
                SigningRegion: region,
            }, nil
        },
    )),
)

Finally, integrate middleBrick into your workflow to continuously verify that your Buffalo endpoints and DynamoDB interactions do not expose missing TLS issues. Use the CLI to scan your API surface:

middlebrick scan https://api.yourapp.com

By combining secure HTTP client settings, strict presigned URL handling, and proactive scanning, you eliminate the cleartext exposure risk while maintaining compatibility with DynamoDB’s HTTPS requirements.