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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.1297
        Advisory (icsa-21-105-01) Schneider Electric C-Bus Toolkit
                               16 April 2021

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

Product:           Schneider Electric C-Bus Toolkit
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-22720 CVE-2021-22719 CVE-2021-22718
                   CVE-2021-22717 CVE-2021-22716 

Original Bulletin: 
   https://us-cert.cisa.gov/ics/advisories/icsa-21-105-01

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ICS Advisory (ICSA-21-105-01)

Schneider Electric C-Bus Toolkit

Original release date: April 15, 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
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1. EXECUTIVE SUMMARY

  o CVSS v3 8.8
  o ATTENTION: Exploitable remotely/low attack complexity
  o Vendor: Schneider Electric
  o Equipment: C-Bus Toolkit
  o Vulnerabilities: Improper Privilege Management, Path Traversal

2. RISK EVALUATION

Successful exploitation of these vulnerabilities may allow remote code
execution.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of C-Bus Toolkit are affected:

  o C-Bus Toolkit v1.15.7 and prior

3.2 VULNERABILITY OVERVIEW

3.2.1 IMPROPER PRIVILEGE MANAGEMENT CWE-269

The affected product is vulnerable to Improper Privilege Management, which
could allow remote code execution when an unprivileged user modifies a file.

CVE-2021-22716 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been assigned; the CVSS vector string is ( AV:L/AC:L/PR:L/UI:N/S:U/C:H/
I:H/A:H ).

3.2.2 IMPROPER LIMITATION OF A PATHNAME TO A RESTRICTED DIRECTORY ('PATH
TRAVERSAL') CWE-22

The affected product is vulnerable to Path Traversal, which could allow remote
code execution when processing config files.

CVE-2021-22717 has been assigned to this vulnerability. A CVSS v3 base score of
8.8 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:N/S:U/C:H/
I:H/A:H ).

3.2.3 IMPROPER LIMITATION OF A PATHNAME TO A RESTRICTED DIRECTORY ('PATH
TRAVERSAL') CWE-22

The affected product is vulnerable to Path Traversal, which could allow remote
code execution when restoring project files.

CVE-2021-22718 has been assigned to this vulnerability. A CVSS v3 base score of
7.8 has been assigned; the CVSS vector string is ( AV:L/AC:L/PR:N/UI:R/S:U/C:H/
I:H/A:H ).

3.2.4 IMPROPER LIMITATION OF A PATHNAME TO A RESTRICTED DIRECTORY ('PATH
TRAVERSAL') CWE-22

The affected product is vulnerable to Path Traversal, which could allow remote
code execution when a file is uploaded.

CVE-2021-22719 has been assigned to this vulnerability. A CVSS v3 base score of
8.8 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:N/S:U/C:H/
I:H/A:H ).

3.2.5 IMPROPER LIMITATION OF A PATHNAME TO A RESTRICTED DIRECTORY ('PATH
TRAVERSAL') CWE-22

The affected product is vulnerable to Path Traversal, which could allow remote
code execution when restoring a project.

CVE-2021-22720 has been assigned to this vulnerability. A CVSS v3 base score of
6.5 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:N/S:U/C:H/
I:N/A:N ).

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: France

3.4 RESEARCHER

rgod, working with Trend Micro Zero Day Initiative, and Simon Zuckerbraun of
Trend Micro's Zero Day Initiative reported these vulnerabilities to CISA.

4. MITIGATIONS

Schneider Electric recommends users update to the latest version available . A
reboot will be needed after the update.
If users choose not to apply the remediation provided above, they should
immediately apply the following mitigations to reduce the risk of exploit:

  o Use an allow list for this application.
  o Turn on the workstation's firewall.
  o Use an antivirus program.
  o Secure the workstation from unauthorized personnel.

Please see Schneider Electric's publication SEVD-2021-103-01 for more
information.

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 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.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.

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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