Exploit Perspective ICM Investigation & Case 5.1.1.16 - Privilege Escalation

[Exploiter]

EDB-ID

43210

Проверка EDB

1. Пройдено

Автор

KONSTANTINOS ALEXIOU

Тип уязвимости

WEBAPPS

Платформа

WINDOWS

CVE

cve-2017-11319

Дата публикации

2017-12-05

Perspective ICM Investigation & Case 5.1.1.16 - Privilege Escalation

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # ## # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
#  Exploit Title: Privilege Escalation - Perspective ICM Investigation & Case - 5.1.1.16
#  Date Reported to vendor: Jun 28, 2017 
#  Date Accepted by vendor: Jun 11, 2017
#  Exploit Author: [email protected]
#  Vendor Homepage: www.resolver.com
#  Version: Perspective ICM Investigation & Case - 5.1.1.16 
#  Tested on: Windows 8.1
#  CVE: CVE-2017-11319
#  CVSS v2 Vector: (AV:A/AC:L/Au:S/C:C/I:C/A:P) 
#  CVSS v2 Score: 7.4
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
According to Resolver site: CIS  "investigations and case management software is an end-to-end, total solution for responding to, reporting on, 
and investigating incidents"  
====================================================Vulnerability description=============================================================
The CIS application permits tampering of users’ permission values which are loaded through the following methods inside the Perspective.data.dll 
just after the initial authentication phase and before the graphical users’ interface is loaded:
 - accessLevels()
 - userEntityPrivs()
 - userFieldPrivs()
The CIS thick client uses the aforementioned methods to set the users’ graphical interface, their permissions access level as well privilege access against 
each GUI field which is retrieved from the database server just  after the initial login phase. Due to insufficient validation methods and missing cross server 
side checking mechanisms, unprivileged authenticated users are allowed to modify their access level permissions by tampering and modifying these values 
thus gaining access to priveleged users actions. An unprivileged user is able by using a C# disassembling and debugging tool such as “dnspy”  to tamper 
these values and gain access on hidden and restricted privileged fields or enable hidden forms such as the “Administration” currently accessible only to the
“CIS Administrators” group. 
======================================================== Proof of Concept ==============================================================

1. Connect to the URL and click on the main button to initiate the installation of the ClickOnce CIS application. 
The CIS application starts downloading various required files which are automatically saved under the following folder:
C:\Users\{Current Logged in User}\AppData\Local\Apps\2.0

2.When the download is finished the main executable “Perspective.exe” is initialized and loaded by the dfsvc.exe which is responsible to check if the application 
is already installed and up to date. 

3. Close the application and open a disassembling and debugging tool such as dnspy. Use the menu “debugger” and choose the option “Debug an assembly”. 
This will open a dialog box to choose an executable for debugging.
Navigate to the main executable “Perspective.exe” which is installed inside the following directory and press OK:
“C:\Users\{Current Logged in User}\AppData\Local\Apps\2.0\Data\{name}.WRL\{name}.AOQ\ pers..tive_f50e2c1eb6078f5b_0005.0001_c760ec4c4b1ffe6d\
The debugger will stop at the main Entry Point of the application. 

4. Click “Continue” from the main menu of the application until the login form appears on the screen. 

5. When the login screen appears, navigate to the “DataHandle” class which is defined inside the “Prespective.data.dll” and should be already decompiled by the dnSpy.

6. Insert breakpoints at the following functions inside the DataHandle Class:
 - UserEntityPrivs
 - UserFieldPrivs
 - UserReportPrivs

7. Login to the application with an unprivileged account and then click Continue from the main menu of the dnSpy. The debugger will stop on the first breakpoint at line 
of the function UserEntityPrivs(). The “foreach” loop used inside these lines calls the UserEntityPrivs() function and sets the users’ allowed permissions against visible 
screens and forms. Click on the Locals field at the bottom menu of the dnSpy and navigate to the entity “useEntityPrivs()” section.
It should be mentioned that the “Administration” menu is restricted only for members belonging to “CIS Administrator” role while the user ITSECAS1 has no access on it.

8. To enable just the administration menu for an unprivileged user just press Continue until the EntityID “Administration” appears in the Locals screen of the dnSpy and 
change the following values to true: 
  - AllowAdd 
  - AllowDelete 
  - AllowEdit 
  - AllowExecute 
  - AllowFullControl 
  - AllowMange 
  - AllowReadOnly 
  - AllowShare
  - Visible

9. Delete the breakpoints and press Continue until the main screen of the thick client appears on the screen. 
While the user is assigned as “Global Head” the administration menu accessible only to the admin users appears on his screen. 
This modification provide access rights to change the minimum Password length to 6 characters 
Additionally, using the aforementioned technique it is possible to enable additional restricted and none visible screens for any unauthorized user. 
It should be also be mentioned that using the same technique it was possible to change the users’ report privileges inside the last “foreach” loop.

10. Finally, and just after the UserReportPrivs foreach loop finishes, we can modify the users’ global membership permissions before they are applied to his interface. 
Finally it should be mentioned that it is possible to access any submenu on the administration menu and modify values with only exception to create a new user.