Operating System:

[Appliance]

Published:

14 November 2019

Protect yourself against future threats.

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             AUSCERT External Security Bulletin Redistribution

                              ESB-2019.3150.2
            US-CERT Advisory (icsa-19-227-04) Siemens SINAMICS
                             14 November 2019

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Siemens SINAMICS products
Publisher:         US-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-6568  

Reference:         ESB-2019.1204

Original Bulletin: 
   https://www.us-cert.gov/ics/advisories/icsa-19-227-04

Comment: This advisory adds additional SINAMICS products to those affected
         and initially published in ESB-2019.1204.

Revision History:  November 14 2019: Updated recommendations from vendor
                   August   16 2019: Initial Release

- --------------------------BEGIN INCLUDED TEXT--------------------

ICS Advisory (ICSA-19-227-04)

Siemens SINAMICS (Update A)

Original release date: November 12, 2019

Legal Notice

All information products included in http://ics-cert.us-cert.gov 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 http://www.us-cert.gov/tlp/ .



1. EXECUTIVE SUMMARY

  o CVSS v3 7.5
  o ATTENTION: Exploitable remotely/low skill level to exploit
  o Vendor: Siemens
  o Equipment: SINAMICS
  o Vulnerability: Uncontrolled Resource Consumption

2. UPDATE INFORMATION

This updated advisory is a follow-up to the original advisory titled
ICSA-19-227-04 Siemens SINAMICS that was published August 15, 2019, on the ICS
webpage on us-cert.gov.

3. RISK EVALUATION

Successful exploitation of this vulnerability may allow an attacker to perform
a denial-of-service attack.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

Siemens reports the vulnerability affects webservers of the following
industrial products:

  o SINAMICS GH150 v4.7 (Control Unit): All versions
  o SINAMICS GH150 v4.8 (Control Unit): All versions prior to v4.8 SP2 HF6
  o SINAMICS GL150 v4.7 (Control Unit): All versions
  o SINAMICS GL150 v4.8 (Control Unit): All versions prior to v4.8 SP2 HF7
  o SINAMICS GM150 v4.7 (Control Unit): All versions
  o SINAMICS GM150 v4.8 (Control Unit): All versions prior to v4.8 SP2 HF9

- --------- Begin Update A Part 1 of 2 ---------

  o SINAMICS SL150 v4.7 (Control Unit): All versions prior to v4.7 HF33

- --------- End Update A Part 1 of 2 ---------

  o SINAMICS SL150 v4.7 (Control Unit): All versions
  o SINAMICS SL150 v4.8 (Control Unit): All versions
  o SINAMICS SM120 v4.7 (Control Unit): All versions
  o SINAMICS SM120 v4.8 (Control Unit): All versions
  o SINAMICS SM150 v4.8 (Control Unit): All versions

4.2 VULNERABILITY OVERVIEW

4.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400

The webserver of the affected devices contains a vulnerability that may lead to
a denial-of-service condition. An attacker may cause a denial-of-service
situation, leading to a restart of the webserver of the affected device. The
security vulnerability could be exploited by an attacker with network access to
the affected systems. Successful exploitation requires no system privileges and
no user interaction.

CVE-2019-6568 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:L/PR:N/UI:N/S:U/
C:N/I:N/A:H ).

4.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Chemical, Commercial Facilities, Critical
    Manufacturing, Energy, Food and Agriculture, Healthcare and Public Health,
    Transportation Systems, Water and Wastewater Systems
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: Germany

4.4 RESEARCHER

Siemens reported this vulnerability to CISA.

5. MITIGATIONS

- --------- Begin Update A Part 2 of 2 ---------

Siemens currently recommends the following updates for the following products:
SINAMICS GH150 v4.7 (Control Unit), SINAMICS GH150 v4.8 (Control Unit, SINAMICS
GL150 v4.7 (Control Unit), SINAMICS GL150 v4.8 (Control Unit), SINAMICS GM150
v4.7 (Control Unit), and SINAMICS GM150 v4.8 (Control Unit)

  o Update to v4.8 SP2 HF9

SINAMICS SL150 v4.7 (Control Unit)

  o Update to v4.7 HF33

SINAMICS SM150 v4.8 (Control Unit)

  o Upgrade to v5.1 SP2 HF3

- --------- End Update A Part 2 of 2 ---------

The update can be obtained from a Siemens representative or via Siemens
customer service.

Siemens has identified the following specific workarounds and mitigations users
can apply to reduce the risk:

  o Restrict network access to the integrated webserver.
  o Deactivate the webserver if not required, and if deactivation is supported
    by the product. For SINAMICS products, webserver may be deactivated with
    parameter P8986 = 0

As a general security measure, Siemens strongly recommends users protect
network access to devices with appropriate mechanisms. In order to operate the
devices in a protected IT environment, Siemens recommends users configure the
environment according to Siemens' operational guidelines for industrial
security , and follow the recommendations in the product manuals.

Additional information on industrial security by Siemens can be found at:

https://www.siemens.com/industrialsecurity

For more information on the vulnerability and more detailed mitigation
instructions, please see Siemens Security Advisory SSA-530931 at the following
location:

http://www.siemens.com/cert/advisories

CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:

  o Locate control system networks and remote devices behind firewalls, and
    isolate them from the business network.
  o When remote access is required, use secure methods, such as Virtual Private
    Networks (VPNs), recognizing that VPNs may have vulnerabilities and should
    be updated to the most current version available. Also recognize that VPN
    is only as secure as the 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 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
Strategies .

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.

No known public exploits specifically target this vulnerability.

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