Fiesta exploit kit landingpage decoder

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Fiesta exploit kit landingpage decoder
@tehsyntx
thembits.blogspot.se

Replace the vars at the bottom with values found in the landingpage.
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function decode(obfuString, intStep, key) {
    var v, i = 0, ykh = 0, buf = '', clearText = '', hexChar, charCode, cy = 0;
    while (i < obfuString.length) {
        ykh = ykh + intStep;
        v = key.indexOf(obfuString.charAt(i));
        v = (v + ykh) % key.length;
        buf += key.charAt(v);
        i++
    }
    for (; cy < buf.length; cy += 2) {
        hexChar = buf.substr(cy, 2);
        charCode = parseInt(hexChar, 16);
        clearText += String.fromCharCode(charCode)
    }
    return clearText
}

var obfuscatedString = '79wep42c6f8rnfai';
var intStep = 15;
var key = 'ia1dpY3w+e75K20fj_bnr98k46c'; //Key found in landingpage

alert(decode(obfuscatedString, intStep, key));