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AUSCERT External Security Bulletin Redistribution
ESB-2021.3440
Advisory (icsa-21-285-01 & (ICSA-21-285-02) Advantech
WebAccess & WebAccess SCADA
15 October 2021
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Advantech WebAccess
Advantech WebAccess SCADA
Publisher: ICS-CERT
Operating System: Windows
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Access Confidential Data -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2021-38431 CVE-2021-38389 CVE-2021-33023
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-21-285-01
https://us-cert.cisa.gov/ics/advisories/icsa-21-285-02
Comment: This bulletin contains two (2) ICS-CERT security advisories.
- --------------------------BEGIN INCLUDED TEXT--------------------
ICS Advisory (ICSA-21-285-01)
Advantech WebAccess SCADA
Original release date: October 12, 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 4.3
o ATTENTION: Exploitable remotely/low attack complexity
o Vendor: Advantech
o Equipment: WebAccess SCADA
o Vulnerability: Missing Authorization
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow an attacker to access
project names and paths.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of WebAccess/SCADA, an HMI platform, are affected:
o WebAccess/SCADA: Versions 9.0.3 and prior
3.2 VULNERABILITY OVERVIEW
3.2.1 MISSING AUTHORIZATION CWE-862
An authenticated user can use API functions to disclose project names and paths
from other users.
CVE-2021-38431 has been assigned to this vulnerability. A CVSS v3 base score of
4.3 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:N/S:U/
C:L/I:N/A:N ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Water and
Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: East Asia, United States, Europe
o COMPANY HEADQUARTERS LOCATION: Taiwan
3.4 RESEARCHER
Peter Cheng from ELEX FEIGONG RESEARCH INSTITUTE of Elex CyberSecurity, Inc.,
reported this vulnerability to CISA.
4. MITIGATIONS
Advantech recommends users upgrade to v9.1.1 or later .
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 this vulnerability.
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.
- --------------------------------------------------------------------------------
ICS Advisory (ICSA-21-285-02)
Advantech WebAccess
Original release date: October 12, 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 9.8
o ATTENTION: Exploitable remotely/low attack complexity
o Vendor: Advantech
o Equipment: WebAccess
o Vulnerabilities: Heap-based Buffer Overflow, Stack-based Buffer Overflow
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to
gain remote code execution.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of WebAccess, an HMI platform, are affected:
o WebAccess Versions 9.02 and prior
3.2 VULNERABILITY OVERVIEW
3.2.1 HEAP-BASED BUFFER OVERFLOW CWE-122
The affected product is vulnerable to a heap-based buffer overflow, which may
allow an attacker to remotely execute code.
CVE-2021-33023 has been assigned to this vulnerability. A CVSS v3 base score of
9.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:H/I:H/A:H ).
3.2.2 STACK-BASED BUFFER OVERFLOW CWE-121
The affected product is vulnerable to a stack-based buffer overflow, which may
allow an attacker to remotely execute code.
CVE-2021-38389 has been assigned to this vulnerability. A CVSS v3 base score of
9.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:H/I:H/A:H ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Water and
Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: East Asia, Europe, United States
o COMPANY HEADQUARTERS LOCATION: Taiwan
3.4 RESEARCHER
Natnael Samson, @NattiSamson, working with Trend Micro's Zero Day Initiative,
reported these vulnerabilities to CISA.
4. MITIGATIONS
Advantech has released Version 9.1.1 to address the stack-based buffer overflow
vulnerability.
In order to address the heap-based buffer overflow vulnerability, Advantech
recommends users directly add the remote access code to avoid being attacked by
unknown requests. This is the remote access code established during
installation of the Advantech WebAccess SCADA software (SCADA node, project
node, or OPC Service) on the OPC Server computer. The access code you enter
here must match the remote access code established during installation on the
OPC Server. This prevents unauthorized users from accessing the OPC Server data
using the Advantech WebAccess SCADA OPC Service.
If you have forgotten the remote access code using during software installation
on the OPC Server node, you have two options:
1. Re-install the Advantech WebAccess SCADA software on the OPC Server node to
change it and edit it to match in your database .
2. Edit the BWSERVER.INI file on the OPC Server node and edit it to match in
your database using UPDATE.
CISA recommends users take defensive measures to minimize the risk of
exploitation of these vulnerabilities. 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.
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--------------------
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