Методы защиты от веб-скрапинга и как их обойти

Web scraping is an automated data collection from websites. It may be needed for various tasks, including information search, creating information catalogs, monitoring changes and updates, as well as web indexing. However, web scraping (also known as parsing) is not always used solely for informational and statistical purposes — it is also employed in several other activities, often related to commercial interests:

• Collecting valuable or paid data;
• Plagiarism or gaining unfair competitive advantages;
• Overloading a specific website’s server (as a form of technical attack);
• Reducing revenue streams of competing sites (parsing bots bypass subscription models);
• Altering website traffic analytics. Therefore, website owners implement protections against scraping, guided by security, legal, and commercial considerations.

Existing methods of web scraping and ways to bypass them

1. Speed limitation or IP blocking. Multiple and overly frequent requests from one IP or a range are detected (e.g., hundreds of requests per second), after which such IPs are blocked or request rates are limited. Bypass methods:

1. IP Rotation, use of IPs from various ranges and geolocations.
2. Setting request delays and random intervals.
3. Injecting random actions between requests to mimic human user behavior.

2. User-Agent filtering. Suspicious or missing HTTP headers are blocked. Bypass methods:

1. Emulating real browser headers.
2. Periodic header changes.
3. Randomizing the User-Agent string between sessions.

3. Executing JavaScript. Data is provided only after full rendering of the webpage by client-side JavaScript, possibly with rendering delays. Bypass methods:

1. Using headless browsers.
2. Using browser-based rendering services.

4. Captcha. Tasks requiring human cognitive functions (recognizing objects in images, text input, rotating objects, etc.). Bypass methods:

1. Using automated or human-assisted Captcha recognition and solving services.
2. Avoiding triggering Captcha services by mimicking human behavior on pages.
3. Using tools to prevent Captcha from appearing.

5. Browser fingerprint recognition. Collecting data and analyzing device properties (WebGL, canvases, fonts, operating system, screen extensions, etc.) accessed during website visits to identify bots. Bypass methods:

1. Hidden plugins.
2. Data substitution tools.
3. Using real browser profiles with periodic rotation.

6. Cookie tracking. Monitoring visit sessions and analyzing their “humanity” behavior. Bypass methods:

1. Handling cookie files with tools that simulate a humanized session.
2. Saving session information between requests.
3. Periodic cookie clearing.

7. Adding invisible fields for filling and submitting forms. Honeypot hidden fields on webpages are usually filled only by bots, not humans, marking them as suspicious. Bypass methods:

1. Analyzing web pages for Honeypots to avoid filling and submitting hidden forms.

8. Authorization based on session-specific tokens. Issuing each visitor tokens for each unique session. Bypass methods:

1. Pre-analyzing the page to detect such tokens before starting data collection requests.

9. Mouse movement analysis. Detecting absence of mouse movement or unnatural movements uncharacteristic of humans. Bypass methods:

1. Simulating natural mouse movement, including scrolling and clicking.
2. Using libraries that mimic human mouse behavior.

10. Traffic pattern analysis. Monitoring request frequency, sequence, timing, and other behaviors that may indicate automation. Bypass methods:

1. Mimicking real human behavior while browsing the site’s page tree.
2. Adding random delays between requests.
3. Scanning pages in unpredictable order.

Conclusion

Modern web scraping is often not harmless, which makes it important for websites to implement protections against it, distinguishing between robots and human users.