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Mohammad Waseem
Mohammad Waseem

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Bypassing Geo-Restrictions: A TypeScript Approach to Testing Geo-Blocked Features

#typescript #security #testing

Bypassing Geo-Restrictions: A TypeScript Approach to Testing Geo-Blocked Features

Testing geo-blocked features is a common challenge for security researchers and developers aiming to ensure proper content delivery across regions. Typically, documentation falls short in guiding how to simulate or bypass such restrictions effectively within local environments. This blog explores how to leverage TypeScript, combined with an understanding of geolocation and network configuration, to test geo-restrictions precisely and efficiently.

Understanding the Context

Geo-restrictions are deployed to control user access based on geographic location, often utilizing IP geolocation services. To test these features locally, we need to simulate different regional environments without actual relocation or relying on undocumented or proprietary tools.

The goal here is to programmatically manipulate the network layer, specifically the IP geolocation, to simulate different regions. We will focus on creating a TypeScript setup that allows switching geolocation data, bypassing restrictions, and ensuring our application's geo-control logic functions correctly.

The Core Strategy

The key insight is that most geo-restriction mechanisms depend on IP information and external geolocation services. Thus, by intercepting or mocking these services, we can generate controlled test scenarios. This involves:

  • Intercepting requests to IP geolocation APIs
  • Returning custom region data
  • Automating tests across multiple regions

Implementing in TypeScript

Step 1: Mocking the Geolocation API

Suppose your application calls an external API like https://api.ipgeolocation.io/ipgeo. You can create a mock server or intercept requests using a tool like fetch-mock or msw (Mock Service Worker). Here's an example using fetch-mock:

import fetchMock from 'fetch-mock';

// Mock different regions
const mockGeoData = (regionCode: string) => {
    fetchMock.get('https://api.ipgeolocation.io/ipgeo', {
        country_code2: regionCode,
        country_name: getCountryName(regionCode),
        // Other geolocation details
    });
};

const getCountryName = (code: string): string => {
    const map: Record<string, string> = {
        "US": "United States",
        "DE": "Germany",
        "IN": "India",
        // Add more as needed
    };
    return map[code] || "Unknown";
};

// Use this function to set the mock for a specific region
mockGeoData('DE');

// Your app logic will now receive German geolocation data for testing.
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Step 2: Automating Region Switching

Create a function to toggle between regions during testing:

async function testRegion(regionCode: string) {
    mockGeoData(regionCode);
    // Trigger the part of your app that depends on geolocation
    await runGeoRestrictedTest();
}

// Example invocation
testRegion('IN');
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Step 3: Verifying Geo-Restrictions

Ensure your application reacts accordingly by asserting responses or UI states based on simulated regions. Incorporate these tests into your CI pipeline for continuous validation.

async function runGeoRestrictedTest() {
    const response = await fetch('/protected-resource');
    const data = await response.json();
    // Check if geo-restriction logic works as expected
    console.assert(data.accessAllowed === true, 'Access should be granted');
}
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Practical Considerations

  • Respect External Dependencies: Avoid manipulating network interfaces directly; instead, intercept APIs used by your app.
  • Maintain Flexibility: Design your mocks to cover multiple regions and edge cases.
  • Security and Compliance: Only perform such tests in controlled environments, never on production systems.

Conclusion

Using TypeScript to simulate geolocation data provides a powerful, flexible, and documented approach to testing geo-restricted features. By mocking external geolocation services, you can verify regional behaviors reliably, accelerating development and ensuring compliance without relying on undocumented or proprietary solutions. This method enhances test coverage, supports continuous integration, and ultimately leads to more resilient, region-aware applications.

References:

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