-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2022.1047
                  Advisory (icsa-22-069-06) Siemens COMOS
                               11 March 2022

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

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

Product:           Siemens COMOS
Publisher:         ICS-CERT
Operating System:  Network Appliance
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-32952 CVE-2021-32950 CVE-2021-32948
                   CVE-2021-32946 CVE-2021-32944 CVE-2021-32940
                   CVE-2021-32938 CVE-2021-32936 CVE-2021-31784
                   CVE-2021-25178 CVE-2021-25177 CVE-2021-25176
                   CVE-2021-25175 CVE-2021-25174 CVE-2021-25173

Original Bulletin: 
   https://us-cert.cisa.gov/ics/advisories/icsa-22-069-06

Comment: CVSS (Max):  7.8 CVE-2021-25173 (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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

ICS Advisory (ICSA-22-069-06)

Siemens COMOS

Original release date: March 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 7.8
  o ATTENTION: Low attack complexity
  o Vendor: Siemens
  o Equipment: COMOS
  o Vulnerabilities: Memory Allocation with Excessive Size Value, Untrusted
    Pointer Dereference, Type Confusion, Stack-based Buffer Overflow,
    Out-of-bounds Write, Out-of-bounds Read, Use After Free, Improper Check for
    Unusual or Exceptional Conditions

2. RISK EVALUATION

Successful exploitation of these vulnerabilities may result in leaked
information or remote code execution in the context of the current process.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Siemens COMOS, a unified platform for collaborative
plan design, are affected:

  o Siemens COMOS: All versions prior to v10.4.1

3.2 VULNERABILITY OVERVIEW

3.2.1 MEMORY ALLOCATION WITH EXCESSIVE SIZE VALUE CWE-789

Open Design Alliance Drawings SDK before 2021.12 contains a memory allocation
with excessive size vulnerability when parsing specially crafted DGN files.
This could allow an attacker to execute code in the context of the current
process.

CVE-2021-25173 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.2 MEMORY ALLOCATION WITH EXCESSIVE SIZE VALUE CWE-789

Open Design Alliance Drawings SDK before 2021.12 contains a memory allocation
with excessive size vulnerability when parsing specially crafted DGN files.
This could allow an attacker to execute code in the context of the current
process.

CVE-2021-25174 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.3 UNTRUSTED POINTER DEREFERENCE CWE-822

Open Design Alliance Drawings SDK before 2021.11 contains a type conversion
vulnerability when parsing specially crafted DXF and DWG files. This could
allow an attacker to execute code in the context of the current process.

CVE-2021-25175 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.4 UNTRUSTED POINTER DEREFERENCE CWE-822

Open Design Alliance Drawings SDK before 2021.11 contains a NULL pointer
dereference vulnerability when parsing DXF and DWG files. This could allow an
attacker to execute code in the context of the current process.

CVE-2021-25176 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.5 ACCESS OF RESOURCE USING INCOMPATIBLE TYPE ('TYPE CONFUSION') CWE-843

Open Design Alliance Drawings SDK before 2021.11 contains a type confusion
issue when parsing specially crafted DXF and DWG files. This could allow an
attacker to execute code in the context of the current process.

CVE-2021-25177 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.6 STACK-BASED BUFFER OVERFLOW CWE-121

Open Design Alliance Drawings SDK before 2021.11 contains a stack-based buffer
overflow vulnerability when parsing specially crafted DXF or DWG files. This
could allow an attacker to execute code in the context of the current process.

CVE-2021-25178 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.7 OUT-OF-BOUNDS WRITE CWE-787

Open Design Alliance Drawings SDK before 2021.6 contains an out-of-bounds write
issue when parsing specially crafted DXF files. This could result in a write
past the end of an allocated buffer and allow an attacker to execute code in
the context of the current process.

CVE-2021-31784 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.8 OUT-OF-BOUNDS WRITE CWE-787

Open Design Alliance Drawings SDK before 2022.4 contains an out-of-bounds write
issue when parsing specially crafted DXF files. This could result in a write
past the end of an allocated buffer and allow an attacker to execute code in
the context of the current process.

CVE-2021-32936 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.9 OUT-OF-BOUNDS READ CWE-125

Open Design Alliance Drawings SDK before 2022.4 are vulnerable to an
out-of-bounds read when parsing specially crafted DWG files. This could allow
an attacker to read sensitive information from memory locations and to cause a
denial-of-service condition.

CVE-2021-32938 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.10 OUT-OF-BOUNDS READ CWE-125

Open Design Alliance Drawings SDK before 2022.4 are vulnerable to an
out-of-bounds read when parsing specially crafted DWG files. This could allow
an attacker to read sensitive information from memory locations and to cause a
denial-of-service condition.

CVE-2021-32940 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.11 USE AFTER FREE CWE-416

Open Design Alliance Drawings SDK before 2021.11 contains a use-after-free
vulnerability when parsing specially crafted DGN files. This could allow an
attacker to execute code in the context of the current process.

CVE-2021-32944 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.12 IMPROPER CHECK FOR UNUSUAL OR EXCEPTIONAL CONDITIONS CWE-754

Open Design Alliance Drawings SDK before 2022.4 are vulnerable to improper
check for unusual or exceptional conditions when parsing specially crafted DGN
files. This could allow an attacker to cause a denial-of-service condition or
execute code in the context of the current process.

CVE-2021-32946 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.13 OUT-OF-BOUNDS WRITE CWE-787

Open Design Alliance Drawings SDK before 2022.4 contains an out-of-bounds write
issue when parsing specially crafted DWG files. This could result in a write
past the end of an allocated buffer and allow an attacker to execute code in
the context of the current process.

CVE-2021-32948 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.14 OUT-OF-BOUNDS READ CWE-125

Open Design Alliance Drawings SDK before 2022.4 are vulnerable to an
out-of-bounds read when parsing specially crafted DXF files. This could allow
an attacker to read sensitive information from memory locations and to cause a
denial-of-service condition.

CVE-2021-32950 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.2.15 OUT-OF-BOUNDS WRITE CWE-787

Open Design Alliance Drawings SDK before 2022.4 contains an out-of-bounds write
issue when parsing specially crafted DGN files. This could result in a write
past the end of an allocated buffer and allow an attacker to execute code in
the context of the current process.

CVE-2021-32952 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been calculated; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Multiple Sectors
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

Siemens recommends upgrading the following software to the most current
version:

  o COMOS: Update to v10.4.1 or later

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

  o Avoid to open untrusted files from unknown sources in COMOS
  o 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 users
    configure the environment according to the Siemens operational guidelines
    for industrial security and follow the recommendations in the product
    manuals

For additional information, please refer to Siemens Security Advisory
SSA-155599

CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. 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 the business network.
  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 on cisa.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 cisa.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 these vulnerabilities. These
vulnerabilities are not exploitable remotely.

For any questions related to this report, please contact the CISA at:

Email: CISAservicedesk@cisa.dhs.gov
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.

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        https://www.auscert.org.au/bulletins/

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967

iQIVAwUBYirXg+NLKJtyKPYoAQhyBw/+NqLnjlbKGMEI8L4f9xHIvvedkOiwXgLj
5tGPFkd4PUbYBurG66kSAM0C1+9O7/MN7phaCx1DA6Ppsnzk7ZeD1A+BgMWiboLt
pBmMNN93xut9McXQiIh7qNzLx08WLeByCzytJ7KaY7+nm5nnLc6VEq8n7yEvjpZn
wGBuqO8vJMxs4WX3I7m64LerVt2Obl1NE5rnN4p98ShbMtqt0CjSQhDCbxobxdK8
l7DnnIuQgKKE6RZuw1uk5PJJjcJxHTM4AbgW93lppQv1NsfIQKhvP/0EFgIqENiS
LTiBB6Q+ObYRSDT1oirMvcTJ0CZ3HAO2Yysb0Id4PR/vZzUKVLN1P4HqRZcSkkXY
KdzlgpDePzy1LqvDKm6JCO+vR374oZZpesWPR+qj6ggs//uVxbM5zkA5iHD4Q3tm
xylBOVRWqFvrBuYqqiYqLLSPaaXX3FlgTr89uawR8k+uz9HvhJVJWIiYXoyD4+8q
yl3sbWjpE4OUZ1pTG/r57954jrp2OWWvN4XN1hjSTthYCvGIrIFY8W2EaKsigcxr
lsMYApkGsCF0zTK1y8z9ukZBr3/AzxuECI1pnbBIQYIbUYcjuJMHS53NDbSRTd32
nCrNdbKC+7ivU6CRFXgu2On0/VLrcW60jjm+at7WkNOS0064WUV+H50cvGI4InwZ
XAlQjIde/PQ=
=E927
-----END PGP SIGNATURE-----