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AUSCERT External Security Bulletin Redistribution
Advisory (icsa-21-110-03) Delta Industrial Automation COMMGR
21 April 2021
AusCERT Security Bulletin Summary
Product: Delta Industrial Automation COMMGR
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Denial of Service -- Remote/Unauthenticated
CVE Names: CVE-2021-27480
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ICS Advisory (ICSA-21-110-03)
Delta Industrial Automation COMMGR
Original release date: April 20, 2021
All information products included in https://us-cert.cisa.gov/ics are provided
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1. EXECUTIVE SUMMARY
o CVSS v3 9.8
o ATTENTION: Exploitable remotely/Low attack complexity
o Vendor: Delta Industrial Automation
o Equipment: COMMGR
o Vulnerability: Stack-based Buffer Overflow
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow for remote code
execution or cause the application to crash, resulting in a denial-of-service
condition in the application server.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of COMMGR, a communication management software, and
accompanying PLC simulators, are affected:
o COMMGR: Version 1.12 and prior
3.2 VULNERABILITY OVERVIEW
3.2.1 STACK-BASED BUFFER OVERFLOW CWE-121
The affected product is vulnerable to a stack-based buffer overflow, which may
allow an attacker to execute remote code.
CVE-2021-27480 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/
o CRITICAL INFRASTRUCTURE SECTORS : Commercial Facilities, Communications,
Critical Manufacturing, Energy, Healthcare and Public Health
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Taiwan
Peter Cheng from CyberSpace Non-Attack Research Institute of Elex
CyberSecurity, Inc., reported this vulnerability to CISA.
Delta Electronics has released COMMGR v1.13 to address this vulnerability and
recommends users to upgrade.
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 also recommends users take the following measures to protect themselves
from social engineering attacks:
o Do not click web links or open unsolicited attachments in email messages.
o Refer to Recognizing and Avoiding Email Scam s for more information on
avoiding email scams.
o Refer to Avoiding Social Engineering and Phishing Attacks for more
information on social engineering attacks.
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
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:
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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