ZTE Ucell 3G Modem App - Privilege Escalation Vulnerability

Type vulnerlab
Reporter Hadji Samir S-dz@hotmail.fr
Modified 2014-12-24T00:00:00


                                            Document Title:
ZTE Ucell 3G Modem App - Privilege Escalation Vulnerability

References (Source):

Release Date:

Vulnerability Laboratory ID (VL-ID):

Common Vulnerability Scoring System:

Product & Service Introduction:
Ucell  application for users to support mobile broadband  (3G) activation for du service provider with systems containing 
one of thesupported devices. It lets you access du wireless internet wherever you are and whenever you need it, all powered 
through your mobile data SIM or simply by connecting your 3G USB stick to your device.

(Copy of the Vendor Homepage: http://ucell.uz/en/subscribers/devices/modems/upgrade_your_modem )

Abstract Advisory Information:
An independent Vulnerability Laboratory Researcher discovered a local privilege escalation vulnerability in the official ZTE Ucell 3G Modem software.

Vulnerability Disclosure Timeline:
2014-12-23:	Public Disclosure (Vulnerability Laboratory)

Discovery Status:

Exploitation Technique:

Severity Level:

Technical Details & Description:
A local privilege escalation vulnerability has been discovered in the official ZTE Ucell 3G Modem application software.
The local security vulnerability allows an attackers to gain higher access privileges by execution of arbitrary codes.

The application is vulnerable to an elevation of privileges vulnerability which can be used by a simple user that can change
the executable file with a binary of choice. The vulnerability exist due to the improper permissions, with the `F` flag (full)
for the `Everyone`(Tout le monde:F) and `Users` group, for the all binary file. The files are installed in the `Ucell Internet`
directory which has the Everyone group assigned to it with full permissions making every single file inside vulnerable to change
by any user on the affected machine. After you replace the binary with your rootkit, on reboot you get SYSTEM privileges.

The security risk of the local privilege escalation vulnerability is estimated as high with a cvss (common vulnerability scoring system) 
count of 6.1. Exploitation of the vulnerability requires a local privileged systen user account without user for interaction. 
Successful exploitation of the privilege escalation web vulnerability results in software- or system compromise.

Proof of Concept (PoC):
The vulnerability can be exploited by local attackers with restricted account privileges and without user interaction.
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.

--- PoC Session Logs ---

C:\Users\s-dz\Desktop>cacls "C:\Program Files\Ucell Internet"
C:\Program Files\Ucell Internet Tout le monde:F
                                Tout le monde:(OI)(CI)(IO)F
                                NT SERVICE\TrustedInstaller:(ID)F
                                NT SERVICE\TrustedInstaller:(CI)(IO)(ID)F
                                AUTORITE NT\Système:(ID)F
                                AUTORITE NT\Système:(OI)(CI)(IO)(ID)F
                                BUILTIN\Utilisateurs:(OI)(CI)(IO)(ID)(accès spécial :)

                                CREATEUR PROPRIETAIRE:(OI)(CI)(IO)(ID)F

C:\Users\s-dz\Desktop>accesschk.exe -dqv "C:\Program Files\Ucell Internet"
C:\Program Files\Ucell Internet
  Medium Mandatory Level (Default) [No-Write-Up]
  RW Tout le monde
  RW NT SERVICE\TrustedInstaller
  RW BUILTIN\Administrateurs
  R  BUILTIN\Utilisateurs


Security Risk:
The security risk of the local privilege escalatation software vulnerability is estimated as high. (CVSS 6.0)

Credits & Authors:
Hadji Samir S-dz@hotmail.fr

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