M573 Session ID Extractor

eagate-session-id-extractor.js

// ==UserScript==
// @name         573 Session ID Extractor
// @namespace    https://r-g.kr/
// @version      2025-03-30
// @description  Extracts 573 session ID. Warning: SESSION ID MUST NOT BE LEAKED!
// @author       Jimin Park
// @match        https://p.eagate.573.jp/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=p.eagate.573.jp
// @grant        GM_cookie
// @run-at       document-end
// ==/UserScript==

(async function() {
    'use strict';

    const cookies = await GM.cookie.list();
    const session_cookie = cookies.find(({name}) => name === 'M573SSID');
    if(!session_cookie) {
        console.error("No session cookie can be found!");
        return;
    }

    const session_id = session_cookie.value;

    const button_elem = document.createElement('button');
    button_elem.textContent = "View Session ID";
    button_elem.style.cursor = 'pointer';

    button_elem.addEventListener('click', () => {
        prompt("Session Key (Keep this private!):", session_id);
    });

    document.body.appendChild(button_elem);
})();

Anyone with your session ID will be able to do anything on behalf of you on the website, so take extra caution not to expose your session ID.

To use this script in Tampermonkey, change the configs as following:

1. Set Config mode to Advanced.
2. Under Security, set Allow scripts to access cookies to All.