HIGH integer overflowecho godynamodb

Integer Overflow in Echo Go with Dynamodb

Integer Overflow in Echo Go with Dynamodb — how this specific combination creates or exposes the vulnerability

An integer overflow in an Echo Go service that interacts with DynamoDB can occur when user-supplied numeric input is used to control pagination, batch sizes, or loop bounds without proper validation. In Go, integer types have fixed widths; for example, int is platform-dependent (32-bit on 32-bit systems, 64-bit on 64-bit systems), and arithmetic operations do not automatically enforce range checks. If an attacker provides a large value for a parameter such as limit or page, the calculation offset := page * limit may wrap around, producing a small or negative-looking integer that bypasses intended limits.

When this computed offset is passed to a DynamoDB query, the request may read unintended portions of a table or consume excessive system resources. DynamoDB itself does not enforce application-level integer semantics, so an invalid offset can still be transmitted, potentially causing excessive read capacity consumption or exposing adjacent data partitions. This pattern intersects with BOLA/IDOR when the offset manipulation allows access to items belonging to other users, and with Input Validation findings when the service does not reject out-of-range values.

In an Echo Go application, routes that accept path or query parameters for pagination are common vectors. For example, a handler like /users/{userID}/items may compute limit and offset from query strings. If the handler uses unchecked arithmetic and passes the result to DynamoDB via the SDK, the overflow may not be detected until unusual behavior appears in logs or during scans. middleBrick detects such risks under its Input Validation and BOLA/IDOR checks, identifying unsafe numeric handling that could lead to data exposure or privilege escalation.

Dynamodb-Specific Remediation in Echo Go — concrete code fixes

To prevent integer overflow when using DynamoDB in Echo Go, validate and sanitize all numeric inputs before using them in arithmetic or SDK calls. Use bounded integer types, explicit range checks, and utility functions that detect overflow. Below are concrete, working examples that demonstrate safe pagination with DynamoDB.

Safe pagination with validation

Instead of directly multiplying user inputs, clamp values to a reasonable range and check for overflow before computing offsets.

package main

import (
	"net/http"
	"math"

	"github.com/labstack/echo/v4"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb"
)

const (
	maxLimit = 1000
)

func safeOffset(page, limit int64) (int64, bool) {
	if page <= 0 || limit <= 0 || limit > maxLimit {
		return 0, false
	}
	if page > (math.MaxInt64 / limit) {
		// page * limit would overflow int64
		return 0, false
	}
	offset := page * limit
	if offset < 0 {
		// should not happen due to above checks, but defensive
		return 0, false
	}
	return offset, true
}

func ItemsHandler(c echo.Context) error {
	p := c.QueryParam("page")
	l := c.QueryParam("limit")
	var page, limit int64
	// Use robust parsing; ignore examples for brevity in this snippet
	// Assume page, limit are parsed with error handling

	offset, ok := safeOffset(page, limit)
	if !ok {
		return c.JSON(http.StatusBadRequest, echo.Map{"error": "invalid pagination parameters"})
	}

	svc := dynamodb.NewFromConfig(cfg)
	resp, err := svc.Query(c.RequestContext(), &dynamodb.QueryInput{
		TableName:                 aws.String("Items"),
		KeyConditionExpression:    aws.String("PK = :pk"),
		ExpressionAttributeValues: map[string]types.AttributeValue{":pk": &types.AttributeValueMemberS{Value: "USER#123"}},
		Limit:                     aws.Int32(int32(limit)),
		ExclusiveStartKey:         map[string]types.AttributeValue{"ID": &types.AttributeValueMemberN{Value: aws.String(fmt.Sprintf("%d", offset))}},
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, echo.Map{"error": err.Error()})
	}
	return c.JSON(http.StatusOK, resp.Items)
}

Rejecting unsafe values early

Apply strict validation at the edge of your handler. Reject negative values, zero limits, and excessively large pages before they reach DynamoDB.

func validatePaginationParams(page, limit int64) error {
	if page < 1 {
		return errors.New("page must be at least 1")
	}
	if limit < 1 || limit > maxLimit {
		return errors.New("limit must be between 1 and " + fmt.Sprint(maxLimit))
	}
	return nil
}

By combining input validation, overflow-aware arithmetic, and bounded DynamoDB parameters, you reduce the risk of integer overflow–driven anomalies. middleBrick’s Input Validation and BOLA checks highlight such numeric handling issues, providing remediation guidance aligned with OWASP API Top 10 and compliance frameworks.

Frequently Asked Questions

Why is DynamoDB not responsible for preventing integer overflow in my Echo Go application?

DynamoDB receives typed requests from your client; it does not interpret Go integer arithmetic. Overflow occurs in application code before values reach DynamoDB, so validation must be implemented in your service.

Can middleBrick detect integer overflow risks in API parameters that affect DynamoDB queries?

Yes. middleBrick’s Input Validation and BOLA/IDOR checks identify unsafe numeric handling, including unchecked arithmetic that could lead to overflow and unintended data access patterns.

Integer Overflow in Echo Go with Dynamodb