1. UA detection

UA detection detects non-browser initiated requests. The website background checks whether a request is abnormal by using the request header of the browser. User-agent User-agent: indicates the identity of the request carrier

Cookie reverse crawl

The principle of climbing

• Cookies can be set for a valid period

• Cookies can have dynamically changing key-value pair data

  Therefore, it is not wise to write cookies to a header dictionary

IP address blocking

In a short period of time, if a site initiates a high-frequency request, the site will blacklist the requested IP

4. Login verification

Verification code 12306

Screenshot Analysis

Hexadecimal use of developer tools

Seven JS confusion

• The server encrypts the implementation of the core JS function
• Processing interpretation anti – obfuscation – brute force cracking