Методы защиты от веб-скрапинга и как их обойти

Web scraping is an automated process of collecting information from websites. It may be required for various tasks, including information searching, creating information catalogs, monitoring changes and updates, as well as web indexing. However, web scraping (also known as parsing) is far from always being used solely for informational and statistical purposes — it is also employed in a number of other tasks, often related to commercial activities:

• 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 competitor sites (parsing bots bypass subscription models);
• Distorting 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 Limiting or IP Blocking. Multiple and excessively frequent requests from a single IP or its range (e.g., hundreds of requests per second) are detected, after which such IPs are blocked or request rates are limited over a given period. Bypass methods:

1. IP Rotation, use of IPs from different ranges and locations.
2. Setting request delays and random intervals.
3. Introducing random actions between requests to imitate human behavior.

1. User-Agent Filtering. Blocking suspicious or missing HTTP headers. Bypass methods:

1. Mimicking real browser headers.
2. Periodic changing of headers.
3. Randomizing the User-Agent string between access sessions.

1. Executing JavaScript. Providing data only after the webpage is fully rendered by client-side JavaScript, possibly with rendering delays. Bypass methods:

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

1. CAPTCHA. Performing tasks related to human cognitive activities (recognizing objects in images, entering text, rotating objects, etc.). Bypass methods:

1. Using automated or human-assisted CAPTCHA recognition and processing services.
2. Avoiding triggering CAPTCHA by imitating human behavior on pages.
3. Using tools to prevent CAPTCHA challenges.

1. Browser Fingerprinting Recognition. Collecting data and analyzing device properties (WebGL, canvases, fonts, operating system, screen extensions, etc.) used to access the website to identify bots. Bypass methods:

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

1. Cookie Tracking. Monitoring visit sessions and analyzing them for “human-like” behavior. Bypass methods:

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

1. Adding Invisible Fields for Filling and Submitting Forms. Honeypot hidden fields are usually filled only by bots, not humans, marking them as suspicious. Bypass methods:

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

1. Session-specific Token-Based Authorization. Providing each visitor with tokens for each unique session. Bypass methods:

1. Preliminary analysis of the page to detect such tokens before starting to send data collection requests.

1. Mouse Movement Analysis. Detecting absence of mouse movements or unnatural movements uncharacteristic of humans. Bypass methods:

1. Mimicking natural mouse movement, including scrolling and clicking.
2. Using libraries that simulate natural mouse behavior.

1. Traffic Pattern Analysis. Tracking request frequency, sequence, timing, and other behaviors that may indicate automation. Bypass methods:

1. Mimicking real human behavior when browsing through website pages.
2. Adding random delays between requests.
3. Crawling pages in unpredictable order.

Conclusion

Modern web scraping is not always harmless, so websites must implement protection methods against it, differentiating between bots and genuine human users.