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AUSCERT External Security Bulletin Redistribution
ESB-2022.5795
ICS Advisory (ICSA-22-314-03) Siemens SINEC Network
Management System Logback Component
11 November 2022
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens SINEC NMS
Publisher: ICS-CERT
Operating System: Network Appliance
Resolution: Patch/Upgrade
CVE Names: CVE-2021-42550
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-22-314-03
Comment: CVSS (Max): 6.6 CVE-2021-42550 (CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H)
CVSS Source: ICS-CERT
Calculator: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
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ICS Advisory (ICSA-22-314-03)
Siemens SINEC Network Management System Logback Component
Original release date: November 10, 2022
Legal Notice
All information products included in https://us-cert.cisa.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://us-cert.cisa.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 6.6
o ATTENTION: Exploitable remotely
o Vendor: Siemens
o Equipment: SINEC NMS
o Vulnerability: Deserialization of Untrusted Data
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow attackers with write
access to the logback configuration file to execute arbitrary code on the
system.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Siemens SINEC NMS, a network management system, are
affected:
o All versions prior to v1.0.3
3.2 VULNERABILITY OVERVIEW
3.2.1 DESERIALIZATION OF UNTRUSTED DATA CWE-502
In Siemens SINEC NMS logback version 1.2.7 and prior, an attacker with the
required privileges to edit configuration files could craft malicious packages
allowing the execution arbitrary code loaded from LDAP servers.
CVE-2021-42550 has been assigned to this vulnerability. A CVSS v3 base score of
6.6 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:H/UI:N/S:U/
C:H/I:H/A:H ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Energy
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
3.4 RESEARCHER
Siemens reported this vulnerability to CISA.
4. MITIGATIONS
Siemens recommends updating to version 1.0.3 or later.
Siemens identified the following workaround and mitigation customers can apply
to reduce risk:
o Restrict the write access to the logback configuration file (logback.xml)
to trusted personnel.
As a general security measure, Siemens 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 Siemens' operational guidelines for industrial security and
following the recommendations in the product manuals.
For more information, see Siemens Security Advisory SSA-371761 in HTML or CSAF
.
CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability these vulnerabilities. Specifically, users
should:
o Minimize network exposure for all control system devices and/or systems,
and ensure they are not accessible from the Internet .
o Locate control system networks and remote devices behind firewalls and
isolate them from business networks.
o When remote access is required, use secure methods, such as Virtual Private
Networks (VPNs), recognizing VPNs may have vulnerabilities and should be
updated to the most current version available. Also recognize VPN is only
as secure as its connected devices.
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 at cisa.gov/ics . Several CISA products detailing cyber
defense best 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 at cisa.gov/ics in the technical information paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
Strategies .
Organizations observing suspected malicious activity should follow established
internal procedures and report findings to CISA for tracking and correlation
against other incidents.
No known public exploits specifically target this vulnerability. This
vulnerability has a high attack complexity.
For any questions related to this report, please contact the CISA at:
Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870
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