Методы защиты от веб-скрапинга и как их обойти

Web scraping is an automated data collection from websites. It can be needed for various tasks, including information search, creation of 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 applied in a number of other tasks, often related to commercial activities:

• Gathering valuable or paid data;
• Plagiarism or gaining an unfair competitive advantage;
• Overloading a particular website's server (as a form of technical attack);
• Reducing the revenue streams of competitors' sites (parsing bots bypass subscription models);
• Distorting website traffic analytics. Therefore, site owners implement protections against parsing, guided by security, legal, and commercial considerations.

Existing Web Scraping Methods and Ways to Circumvent Them

1. Speed limitations or IP blocking. Multiple and too frequent requests from a single IP or its range (for example, hundreds of requests per second) are detected, after which such IPs are blocked or limited in request frequency within a certain time frame. Circumvention methods:

1. IP Rotation, using IPs from different ranges and geographies.
2. Setting request delays and random intervals.
3. Injecting random actions between requests to imitate human user behavior.

1. User-Agent filtering. Blocking suspicious or missing HTTP headers. Circumvention methods:

1. Mimicking legitimate headers of real browsers.
2. Periodically changing headers.
3. Randomizing the User-Agent string between sessions.

1. Executing JavaScript. Delivering data only after full rendering of the web page by client-side JavaScript, possibly with rendering delays. Circumvention methods:

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

1. Captcha. Performing tasks associated with human cognitive activity (recognizing objects in images, inputting text, rotating objects, etc.). Circumvention methods:

1. Using automated or human-assisted recognition and processing services.
2. Avoiding invoking Captcha services by mimicking human behavior on pages.
3. Using tools to prevent the triggering of Captcha services.

1. Browser fingerprint recognition. Collecting data and analyzing device properties (WebGL, canvases, fonts, operating system, screen extensions, etc.) used to access the website, for bot detection. Circumvention methods:

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

1. Tracking cookies. Monitoring visit sessions and analyzing their 'human-like' behavior. Circumvention methods:

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

1. Adding invisible fields for filling and submitting forms. Hidden Honeypot fields on web pages are usually filled only by bots, not humans, marking them as suspicious. Circumvention methods:

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

1. Session-specific token authorization. Issuing tokens to each visitor for each unique session. Circumvention methods:

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

1. Mouse movement analysis. Detects absence of mouse movements or unnatural, uncharacteristic movements for humans. Circumvention 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. Circumvention methods:

1. Simulating real human behavior when browsing the site's page tree.
2. Adding random delays between requests.
3. Scanning pages in unpredictable order.

Conclusion

Modern web scraping is far from always harmless, so websites need to implement protective methods against it, differentiating between robots and human users.