InstantHMI 6.1 Privilege Escalation

`itle: InstantHMI - EoP: User to ADMIN  
CWE Class: CWE-276: Incorrect Default Permissions  
Date: 01/06/2016  
Vendor: Software Horizons  
Product: InstantHMI  
Version: 6.1   
Download link: http://www.instanthmi.com/ihmisoftware.htm  
Tested on: Windows 7 x86, fully patched  
Release mode: no bugbounty program, public release  
  
Installer Name: IHMI61-PCInstall-Unicode.exe  
MD5: ee3ca3181c51387d89de19e89aea0b31  
SHA1: c3f1929093a3bc28f4f8fdd9cb38b1455d7f0d6f  
  
- 1. Introduction: -  
During a standard installation (default option) the installer   
automatically creates a folder named "IHMI-6" in the root drive.   
No other location can be specified during standard installation.  
  
As this folder receives default permissions AUTHENTICATED USERS   
are given the WRITE permission.   
  
Because of this they can replace binaries or plant malicious   
DLLs to obtain elevated, administrative level, privileges.  
  
- 2. Technical Details/PoC: -  
A. Obtain and execute the installer.   
  
B. Observe there is no prompt for the installation location.  
  
C. Review permissions under the Explorer Security tab or run icacls.exe  
  
Example:  
  
IHMI-6 BUILTIN\Administrators:(I)(F)  
BUILTIN\Administrators:(I)(OI)(CI)(IO)(F)  
NT AUTHORITY\SYSTEM:(I)(F)  
NT AUTHORITY\SYSTEM:(I)(OI)(CI)(IO)(F)  
BUILTIN\Users:(I)(OI)(CI)(RX)  
NT AUTHORITY\Authenticated Users:(I)(M)  
NT AUTHORITY\Authenticated Users:(I)(OI)(CI)(IO)(M)  
  
Successfully processed 1 files; Failed processing 0 files  
  
D. Change the main executable: InstantHMI.exe with a malicious copy.   
  
E. Once executed by an administrator our code will run   
under administrator level privileges.  
  
- 3. Mitigation: -  
A. Install under "c:\program files" or "C:\Program Files (x86)"  
  
B. set appropriate permissions on the application folder.  
  
- 4. Author: -  
sh4d0wman  
  
`