[Tutorial] South China University of Technology campus network login packet capture and protocol simulation

It is very troublesome to log in manually every time, and it is interrupted from time to time, so it is more convenient to create a script to monitor it regularly, disconnect and reconnect. I won’t talk about how to write this script here, just record the packet capture content when logging in.

Don't worry, let's go straight to the analysis. It's not complicated and I believe everyone can understand it at a glance.

Table of contents

Packet capture analysis

postman test request

python simulation

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Packet capture analysis

Login address of the office area network: https://172.25.31.129:9444/

For Base64 encoding, you can see here: Base64 online encoding and decoding | Base64 encryption and decryption - Base64.us

Extract main information:

请求 URL:
https://172.25.31.129:9444/byod/byodrs/login/defaultLogin

请求方法:
POST

请求头:
cookie=testcookie=yes; userip=分给你的IP,连上WiFi就会给你

请求负载:(为方便展示，实际请求时候不要有空格或者换行)
{
    "username":"你的学号",
    "userPassword":"登录密码并使用base64编码",
    "serviceSuffixId":"-1",
    "dynamicPwdAuth":false,
    "code":"",
    "codeTime":"",
    "validateCode":"",
    "licenseCode":"",
    "userGroupId":0,
    "validationType":0,
    "guestManagerId":0,
    "shopIdE":null,
    "wlannasid":null
}

Postman test request

Python simulation

import requests
import socket

def get_local_ip():
    ip_address = ''
    try:
        hostname = socket.gethostname()
        ip_address = socket.gethostbyname(hostname)
    except:
        pass
    return ip_address


url = r'https://172.25.31.129:9444/byod/byodrs/login/defaultLogin'
data = {"userName":"学号","userPassword":"密码的base64编码","serviceSuffixId":"-1","dynamicPwdAuth":False,"code":"","codeTime":"","validateCode":"","licenseCode":"","userGroupId":0,"validationType":0,"guestManagerId":0,"shopIdE":None,"wlannasid":None}
headers = {"cookie":"testcookie=yes; userip="+get_local_ip()}


res = requests.post(url, json=data, headers=headers, verify=False).text
print(res)