Phishing Api Keys in Echo Go with Dynamodb

When an Echo Go service stores or references API keys in a DynamoDB table and exposes an endpoint that returns those keys or related metadata, it can enable phishing workflows. A common pattern is a configuration or settings endpoint that echoes back stored credentials for debugging or migration purposes. If that endpoint does not enforce authentication and strict input validation, an attacker can supply a malicious parameter that causes the service to return valid API keys stored in DynamoDB.

DynamoDB itself does not cause phishing, but the way data is modeled and accessed can amplify risk. For example, storing keys in a table with a partition key like user_id and retrieving items without verifying the requester’s authorization can lead to Insecure Direct Object References (IDOR). If the Echo Go handler uses raw query parameters to construct DynamoDB queries, an attacker may manipulate the input to enumerate or exfiltrate keys belonging to other users. This becomes a phishing vector when the keys are returned in error messages, debug responses, or overly verbose API outputs that can be captured by the attacker.

Another scenario involves log or audit endpoints that read from DynamoDB and display sensitive configuration. If those endpoints are unauthenticated or weakly authenticated, an attacker can use social engineering to trick a victim into visiting a crafted URL that calls the endpoint and reveals API keys. Because Echo Go applications often integrate with DynamoDB using the AWS SDK, improper handling of credentials in the application layer (for example, using shared config files with broad permissions) can also increase the impact of any leaked key.

During a middleBrick scan, checks such as Authentication, Input Validation, Data Exposure, and LLM/AI Security are particularly relevant. Authentication verifies whether endpoints that access DynamoDB require valid credentials. Input Validation ensures that user-controlled parameters cannot manipulate queries to return unexpected data. Data Exposure checks whether responses inadvertently include sensitive fields like API keys. The LLM/AI Security checks can detect whether key-like outputs are exposed through model endpoints or logs, and whether prompts or responses leak credentials stored in DynamoDB.

Secure handling of API keys in DynamoDB within an Echo Go application starts with strict access controls and precise query construction. Always authenticate and authorize every request before performing any DynamoDB operations. Use IAM roles and policies that grant least privilege, and avoid retrieving raw API keys in responses unless absolutely necessary.

When storing and retrieving items, prefer parameterized queries and avoid concatenating user input into expression strings. Use the AWS SDK for Go (v2) with strongly typed structures and condition expressions to ensure you are accessing only the intended items.

// Example: Retrieve an item by a known partition key and explicit attribute name
package main

import (
	"context"
	"fmt"
	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb/types"
)

ttype APIKeyRecord struct {
	UserID      string `json:"user_id"`
	ServiceName string `json:"service_name"`
	APIKey      string `json:"api_key"` // store only when necessary; prefer references
}

func GetAPIKey(ctx context.Context, client *dynamodb.Client, tableName, userID, serviceName string) (string, error) {
	key := map[string]types.AttributeValue{
		"user_id":      &types.AttributeValueMemberS{Value: userID},
		"service_name": &types.AttributeValueMemberS{Value: serviceName},
	}
	resp, err := client.GetItem(ctx, &dynamodb.GetItemInput{
		TableName: aws.String(tableName),
		Key:       key,
	})
	if err != nil {
		return "", fmt.Errorf("get item failed: %w", err)
	}
	if len(resp.Item) == 0 {
		return "", fmt.Errorf("item not found")
	}
	var record APIKeyRecord
	// Safe unmarshalling using aws.UnmarshalMap
	if err := aws.UnmarshalMap(resp.Item, &record); err != nil {
		return "", fmt.Errorf("unmarshal failed: %w", err)
	}
	// Avoid returning raw API keys in production; return a reference or hash instead
	return record.APIKey, nil
}

In Echo Go, ensure route handlers validate and sanitize all inputs before building DynamoDB queries. Do not allow user-controlled parameters to dictate which attributes are returned or which items are filtered. Instead, use fixed query patterns and enforce authorization checks that confirm the requesting user owns the requested resource.

// Example: Echo handler with input validation and authorization
package main

import (
	"net/http"
	"github.com/labstack/echo/v4"
)

type KeyResponse struct {
	APIKey string `json:"api_key,omitempty"`
	// Prefer returning metadata or a token instead of the raw key
}

func GetKeyHandler(c echo.Context) error {
	userID := c.Param("user_id")
	serviceName := c.QueryParam("service")
	// Validate input: enforce allowed service names and format for user_id
	if !isValidUserID(userID) || !isValidService(serviceName) {
		return echo.NewHTTPError(http.StatusBadRequest, "invalid parameters")
	}
	// Ensure the request is authorized for this user_id
	if c.Get("user_id") != userID {
		return echo.NewHTTPError(http.StatusForbidden, "unauthorized")
	}
	key, err := GetAPIKey(c.Request().Context(), dbClient, "api_keys_table", userID, serviceName)
	if err != nil {
		return echo.NewHTTPError(http.StatusInternalServerError, "unable to retrieve key")
	}
	// Avoid exposing raw keys; consider returning a reference or removing this line in production
	return c.JSON(http.StatusOK, KeyResponse{APIKey: key})
}

func isValidUserID(id string) bool {
	// Implement strict validation: e.g., UUID format or alphanumeric pattern
	return len(id) > 0
}

func isValidService(s string) bool {
	allowed := map[string]bool{"email_service": true, "payment_gateway": true}
	return allowed[s]
}

Remediation also involves periodic review of DynamoDB tables to identify and remove or rotate exposed keys. Use middleBrick’s Pro plan for continuous monitoring and automated alerts when risky configurations are detected. Its GitHub Action can enforce security gates in CI/CD, ensuring that new deployments do not introduce insecure DynamoDB access patterns. For local development and deeper analysis, the CLI tool allows you to run on-demand scans from the terminal with middlebrick scan <url>.