Distributed Data Systems WebHMI

1. EXECUTIVE SUMMARY

• CVSS v3 10.0
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Distributed Data Systems
• Equipment: WebHMI
• Vulnerabilities: Authentication Bypass by Primary Weakness, Unrestricted Upload of File with Dangerous Type

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an administrator account login without password authentication and remote code execution with root privileges.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of WebHMI, a SCADA system with built-in web server capability, are affected:

• All versions prior to 4.1

3.2 VULNERABILITY OVERVIEW

3.2.1    AUTHENTICATION BYPASS BY PRIMARY WEAKNESS CWE-305

The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness primary to the authentication error.

CVE-2021-43931 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    UNRESTRICTED UPLOAD OF FILE WITH DANGEROUS TYPE CWE-434

The software allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product’s environment or lead to arbitrary code execution.

CVE-2021-43936 has been assigned to this vulnerability. A CVSS v3 base score of 10.0 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Germany, Poland, Ukraine, United States
• COMPANY HEADQUARTERS LOCATION: Ukraine

3.4 RESEARCHER

Marcin Dudek of CERT.PL reported these vulnerabilities to CISA.

4. MITIGATIONS

Distributed Data Systems recommends:

• Upgrading the platform software to the latest release, Version 4.1

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that 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 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.

• Distributed Data Systems