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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.2046
        Advisory (icsa-21-159-02) Open Design Alliance Drawings SDK
                                9 June 2021

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

Product:           Open Design Alliance Drawings SDK
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Denial of Service               -- Existing Account
                   Access Confidential Data        -- Existing Account
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 

Original Bulletin: 
   https://us-cert.cisa.gov/ics/advisories/icsa-21-159-02

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ICS Advisory (ICSA-21-159-02)

Open Design Alliance Drawings SDK

Original release date: June 08, 2021

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: Open Design Alliance
  o Equipment: Drawings SDK
  o Vulnerabilities: Out-of-bounds Read, Out-of-bounds Write, Improper check
    for Unusual or Exceptional Conditions, Use After Free

2. RISK EVALUATION

Successful exploitation of these vulnerabilities may allow code execution in
the context of the current process or cause a denial-of-service condition.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Drawings SDK, a software development kit for DWG and
DGN, are affected:

  o Drawings SDK: All versions prior to 2022.4
  o Drawing SDK: Version 2022.4 is affected by CVE-2021-32946 and
    CVE-2021-32952

3.2 VULNERABILITY OVERVIEW

3.2.1 OUT-OF-BOUNDS READ CWE-125

The affected products are vulnerable to an out-of-bounds read due to parsing of
DWG files resulting from the lack of proper validation of user-supplied data.
This can result in a read past the end of an allocated buffer and allows
attackers to cause a denial-of service condition or read sensitive information
from memory.

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

3.2.2 OUT-OF-BOUNDS WRITE CWE-787

An out-of-bounds write issue exists in the DXF file-recovering procedure
resulting from the lack of proper validation of user-supplied data. This can
result in a write past the end of an allocated buffer and allow attackers to
cause a denial-of-service condition or 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 ).

3.2.3 OUT-OF-BOUNDS READ CWE-125

An out-of-bounds read issue exists in the DWG file-recovering procedure
resulting from the lack of proper validation of user-supplied data. This can
result in a read past the end of an allocated buffer and allow attackers to
cause a denial-of-service condition or read sensitive information from memory
locations.

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

3.2.4 IMPROPER CHECK FOR UNUSUAL OR EXCEPTIONAL CONDITIONS CWE-754

An improper check for unusual or exceptional conditions issue exists within the
parsing DGN files resulting from the lack of proper validation of the
user-supplied data. This may result in several of out-of-bounds problems and
allow attackers 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 ).

3.2.5 OUT-OF-BOUNDS WRITE CWE-787

An out-of-bounds write issue exists in the DWG file-reading procedure resulting
from the lack of proper validation of user-supplied data. This can result in a
write past the end of an allocated buffer and allow attackers to cause a
denial-of-service condition or 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 ).

3.2.6 OUT-OF-BOUNDS READ CWE-125

An out-of-bounds read issue exists within the parsing of DXF files in the
affected product resulting from the lack of proper validation of user-supplied
data. This can result in a read past the end of an allocated buffer and allows
attackers to cause a denial-of-service condition or read sensitive information
from memory locations.

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

3.2.7 OUT-OF-BOUNDS WRITE CWE-787

An out-of-bounds write issue exists in the DGN file-reading procedure in the
affected product resulting from the lack of proper validation of user-supplied
data. This can result in a write past the end of an allocated buffer and allow
attackers to cause a denial-of-service condition or 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 ).

3.2.8 USE AFTER FREE CWE-416

A use-after-free issue exists in the DGN file-reading procedure in the affected
product resulting from the lack of proper validation of user-supplied data.
This can result in a memory corruption or arbitrary code execution, allowing
attackers to cause a denial-of-service condition or 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 ).

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Multiple
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

Mat Powell and Brian Gorenc of Trend Micro's Zero Day Initiative reported these
vulnerabilities to CISA. Siemens ProductCERT assisted coordination with Open
Design Alliance.

4. MITIGATIONS

Open Design Alliance recommends updating to v2022.5 or later (login and ODA
membership required).

For more information refer to Open Design Alliance's Security Advisories .

CISA recommends users take the following measures to protect themselves from
social engineering attacks:

  o Only use project files from trusted sources.
  o Ensure the least-privilege user principle is followed.
  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 Avoiding Social Engineering and Phishing Attacks for more
    information on social engineering attacks.

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 that 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 us-cert.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 us-cert.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.

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