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AUSCERT External Security Bulletin Redistribution
Advisory (icsa-20-196-03) Siemens SICAM MMU, SICAM T, and SICAM SGU
15 July 2020
AusCERT Security Bulletin Summary
Product: Siemens SICAM MMU
Siemens SICAM SGU
Siemens SICAM T
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Increased Privileges -- Remote/Unauthenticated
Cross-site Scripting -- Remote with User Interaction
Access Confidential Data -- Remote/Unauthenticated
Provide Misleading Information -- Remote with User Interaction
CVE Names: CVE-2020-10045 CVE-2020-10044 CVE-2020-10043
CVE-2020-10042 CVE-2020-10041 CVE-2020-10040
CVE-2020-10039 CVE-2020-10038 CVE-2020-10037
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ICS Advisory (ICSA-20-196-03)
Siemens SICAM MMU, SICAM T, and SICAM SGU
Original release date: July 14, 2020
All information products included in https://us-cert.gov/ics are provided"as
is" for informational purposes only. The Department of Homeland Security (DHS)
does not provide any warranties of any kind regarding any information contained
within. DHS does not endorse any commercial product or service, referenced in
this product or otherwise. Further dissemination of this product is governed by
the Traffic Light Protocol (TLP) marking in the header. For more information
about TLP, see https://www.us-cert.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 9.8
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: SICAM MMU, SICAM T and SICAM SGU
o Vulnerabilities: Out-of-bounds Read, Missing Authentication for Critical
Function, Missing Encryption of Sensitive Data, Use of Password Hash with
Insufficient Computational Effort, Cross-site Scripting, Classic Buffer
Overflow, Basic XSS, Authentication Bypass by Capture-replay
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to
affect the availability, read sensitive data, and gain remote code execution on
the affected devices.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following Siemens products are affected:
o SICAM MMU: All versions prior to 2.05
o SICAM SGU: All versions
o SICAM T: All versions prior to 2.18
3.2 VULNERABILITY OVERVIEW
3.2.1 OUT-OF-BOUNDS READ CWE-125
By performing a flooding attack against the web server, an attacker might be
able to gain read access to the device's memory, and reveal confidential
CVE-2020-10037 has been assigned to this vulnerability. A CVSS v3 base score of
5.9 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:U/
3.2.2 MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306
An attacker with access to the device's web server might be able to execute
administrative commands without authentication.
CVE-2020-10038 has been assigned to this vulnerability. A CVSS v3 base score of
9.8 has been calculated; the CVSS vector string is (A V:N/AC:L/PR:N/UI:N/S:U/
3.2.3 MISSING ENCRYPTION OF SENSITIVE DATA CWE-311
An attacker in a privileged network position between a legitimate user and the
web server might be able to conduct a man-in-the-middle attack and gain read
and write access to the transmitted data.
CVE-2020-10039 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:R/S:U/
3.2.4 USE OF PASSWORD HASH WITH INSUFFICIENT COMPUTATIONAL EFFORT CWE-916
An attacker with local access to the device might be able to retrieve passwords
in clear text.
CVE-2020-10040 has been assigned to this vulnerability. A CVSS v3 base score of
6.2 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:N/S:U/
3.2.5 IMPROPER NEUTRALIZATION OF INPUT DURING WEB PAGE GENERATION ('CROSS-SITE
A stored cross-site-scripting (XSS) vulnerability is present in different
locations of the web application. An attacker might be able to take over a
session of a legitimate user.
CVE-2020-10041 has been assigned to this vulnerability. A CVSS v3 base score of
9.6 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:C/
3.2.6 BUFFER COPY WITHOUT CHECKING SIZE OF INPUT ('CLASSIC BUFFER OVERFLOW')
A buffer overflow in various positions of the web application might enable an
attacker with access to the web application to execute arbitrary code over the
CVE-2020-10042 has been assigned to this vulnerability. A CVSS v3 base score of
9.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
3.2.7 IMPROPER NEUTRALIZATION OF SCRIPT-RELATED HTML TAGS IN A WEB PAGE (BASIC
The web server could allow cross-site scripting (XSS) attacks if unsuspecting
users are tricked into accessing a malicious link.
CVE-2020-10043 has been assigned to this vulnerability. A CVSS v3 base score of
8.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:C/
3.2.8 MISSING AUTHENTICATION FOR A CRITICAL FUNCTION CWE-306
An attacker with access to the network could be able to install specially
crafted firmware on the device.
CVE-2020-10044 has been assigned to this vulnerability. A CVSS v3 base score of
9.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
3.2.9 AUTHENTICATION BYPASS BY CAPTURE-REPLAY CWE-294
An error in the challenge-response procedure could allow an attacker to replay
authentication traffic and gain access to protected areas of the web
CVE-2020-10045 has been assigned to this vulnerability. A CVSS v3 base score of
8.3 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:U/
o CRITICAL INFRASTRUCTURE SECTORS: Chemical, Energy, Food and Agriculture,
Water and Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
Siemens thanks the following parties for their efforts:
o Luca Simburger, Luca Hofschuster, Lukas Kahnert, Jakob Lachermeier,
Christian Costa, Simon Huber, Lukas Sas Brunschier, Florian Freiberger,
Florian Burger, Marie-Louise Oostveen, Magdalena Thomeczek, and Johann
Uhrmann from Landshut University of Applied Sciences.
o Max Hirschberger, Simon Hofmann, and Peter Knauer from Augsburg University
of Applied Sciences.
Siemens recommends applying updates, where available:
o SICAM MMU: Update to v2.05
o SICAM SGU: For RTU applications, upgrade the discontinued SICAM SGU devices
to SICAM A8000 RTUs.
o SICAM T: Update to v2.18
Siemens has identified the following specific workarounds and mitigations that
users can apply to reduce the risk:
o The firmware updates to SICAM T and SICAM MMU introduce authentication to
the web application and remove some unnecessary functionality. The web
authentication functionality reduces the risk of access to the device's web
application for executing administrative commands by unauthenticated users.
o Due to hardware constraints, encryption is not possible on the devices.
Confidential data such as passwords handled by the devices need to be
protected on the network by other means, e.g., by VPN.
o The risk for remote code execution and unauthenticated firmware
installation can be mitigated by ensuring encryption and authentication
between the user and the device, e.g., by VPN.
o Use a modern and up to date browser.
As a general security measure, Siemens strongly recommends protecting network
access to devices with appropriate mechanisms. In order to operate the devices
in a protected IT environment, Siemens recommends configuring the environment
according to the Siemens operational guidelines for Industrial Security and
following the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory
CISA reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices
on the ICS webpage on us-cert.gov . Several recommended practices are available
for reading and download, including Improving Industrial Control Systems
Cybersecurity with Defense-in-Depth Strategies .
Additional mitigation guidance and recommended practices are publicly available
on the ICS webpage on us-cert.gov in the Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
Organizations observing any suspected malicious activity should follow their
established internal procedures and report their findings to CISA for tracking
and correlation against other incidents.
CISA also recommends users take the following measures to protect themselves
from social engineering attacks:
o Do not click web links or open unsolicited attachments in email messages.
o Refer to Recognizing and Avoiding Email Scams for more information on
avoiding email scams.
o Refer to A voiding Social Engineering and Phishing Attacks for more
information on social engineering attacks.
No known public exploits specifically target these vulnerabilities.
For any questions related to this report, please contact the CISA at:
Toll Free: 1-888-282-0870
CISA continuously strives to improve its products and services. You can help by
choosing one of the links below to provide feedback about this product.
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