Delta Industrial Automation COMMGR

1. EXECUTIVE SUMMARY

• CVSS v3 9.8
• ATTENTION: Exploitable remotely/Low attack complexity
• Vendor: Delta Industrial Automation
• Equipment: COMMGR
• 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:

• 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/C:H/I:H/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Communications, Critical Manufacturing, Energy, Healthcare and Public Health
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Taiwan

3.4 RESEARCHER

Peter Cheng from CyberSpace Non-Attack Research Institute of Elex CyberSecurity, Inc., reported this vulnerability to CISA.

4. MITIGATIONS

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:

• Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls and isolate them from the business network.
• 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:

• Do not click web links or open unsolicited attachments in email messages.
• Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
• 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 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.

• Delta Industrial Automation