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List:       full-disclosure
Subject:    [FD] [CVE-2017-11321] UCOPIA Wireless Appliance < 5.1.8 Restricted Shell Escape
From:       Sysdream Labs <labs () sysdream ! com>
Date:       2017-09-29 13:01:27
Message-ID: 89daa805-6ad8-8738-dc2b-0b248716da38 () sysdream ! com
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# [CVE-2017-11321] UCOPIA Wireless Appliance < 5.1.8 Restricted Shell Escape

## Asset Description

UCOPIA solutions bring together a combination of software, appliance and cloud services serving \
small to large customers.

More than 12,000 UCOPIA solutions are deployed and maintained by UCOPIA expert partners all \
over the world.

The affected asset in this report is a WiFi management appliance.


## Vulnerability

Shell Escape via `less` command.

**Threat**

Improper sanitization of system commands in the restricted shell interface in UCOPIA Wireless \
Appliance, prior to 5.1.8, allows remote attackers to gain access to a system shell as the \
"admin" user.

**CVE ID**: CVE-2017-11321

**Access Vector**: network

**Security Risk**: critical

**Vulnerability**: CWE-78

**CVSS Base Score**: 9.1 (Critical)

**CVSS Vector**: CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

### Proof of Concept: Restricted Shell Escape

By default, the UCOPIA wireless appliances exposes two shell access on port 22 (SSH) and 222 \
(ShellInTheBox).

A documented **admin** user exists on the system with the password **bhu85tgb**.

Quoted from the documentation :

> You can also retrieve the IP address of the outgoing interface. For this, you need to log in \
> to the terminal of the virtual machine with
the following username and password: admin/bhu85tgb, and then execute the interface command.

By logging in within these interfaces, we can access to a restricted shell (*clish*) that \
allows only a few commands.

However, the `less` command is allowed, and because `less` allows to execute shell commands \
when viewing a file, we can use it to escape the restricted shell.

Steps :

**1/** Login to the appliance using SSH or ShellInTheBox.

**2/** Run the `less /etc/passwd` command.

**3/** When viewing the file, type `!sh`

**4/** You now have unrestricted `admin` user access to the appliance.

```
> less /etc/passwd
!sh
$ ls /
bin dev etc home lib proc tmp user
$ whoami
admin
```

## Solution

Update to UCOPIA 5.1.8

## Timeline (dd/mm/yyyy)

* 08/03/2017 : Vulnerability discovery.
* 03/05/2017 : Initial contact.
* 10/05/2017 : GPG Key exchange.
* 10/05/2017 : Advisory sent to vendor.
* 17/05/2017 : Request for feedback.
* 22/05/2017 : Vendor acknowledge the vulnerabilities.
* 21/06/2017 : Sysdream Labs request for an ETA, warning for public disclosure.
* 21/06/2017 : Vendor say that the UCOPIA 5.1.8 fixes the issue.
* 29/09/2017 : Public disclosure.

## Credits

* Nicolas CHATELAIN, Sysdream (n.chatelain -at- sysdream -dot- com)

-- 
SYSDREAM Labs <labs@sysdream.com>

GPG :
47D1 E124 C43E F992 2A2E
1551 8EB4 8CD9 D5B2 59A1

* Website: https://sysdream.com/
* Twitter: @sysdream


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