HP ThinPro - Privilege escalation
===============================================================================

Identifiers
-------------------------------------------------
* CVE-2019-16287

CVSSv3 score
-------------------------------------------------
6.1 (AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N)

Vendor
-------------------------------------------------
HP - [https://www.hp.com](https://www.hp.com)

Product
-------------------------------------------------
Deliver secure desktop virtualization that’s as comfortable for IT as it is
for end users with the stunningly redesigned HP ThinPro. It has a bold new
user interface and workflow refinements that make it a breeze to configure,
manage, and use right out of the box.

Affected versions
-------------------------------------------------
 - HP ThinPro Linux 7.1
 - HP ThinPro Linux 7.0
 - HP ThinPro Linux 6.2.1
 - HP ThinPro Linux 6.2

Credit
-------------------------------------------------
Eldar Marcussen - xen1thLabs - Software Labs

Vulnerability summary
-------------------------------------------------
The ThinPro platform relies on the presence of a file to determine if it is
operating in Administrative or User mode. An unauthenticated attacker
can leverage functionality in privileged processes to create this file
which enables adminstrative access to the device.

Technical details
------------------------------------------------
An attacker can use features of applications that are running with
privileges by default to create the administrative flag file
`/var/run/hptc-admin` which enables the administrative options in the user
interface. The attacker can then simply start a a terminal session with
root privileges from the start menu.

Proof of concept
-------------------------------------------------
The following evidence is provided to illustrate the existence and
exploitation:

 1. From the start menu select Control panel
 2. Open the Hardware section
 3. CLick on printers
 4. In the new printers window press F1
 5. Click Forward
 6. Select `Not listed` and then click Forward
 7. Click Forward
 8. Select `Not listed` and then click Forward
 9. Click forward
10. Click save
11. Replace `troubleshoot.txt` with `/var/run/hptc-admin` as the file name
12. Click save
13. Observe the red desktop border indicating adminstrative operation mode
14. From the start menu, select Tools -> X terminal
15. Observe X terminal spawning with root privileges

Solution
-------------------------------------------------
Contact vendor for a solution

Timeline
-------------------------------------------------
Date        | Status
------------|-----------------------------
19-AUG-2019 | Reported to vendor
22-NOV-2019 | Patch available
24-MAR-2020 | Public disclosure