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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.4100
         Advisory (icsa-21-336-03) Distributed Data Systems WebHMI
                              3 December 2021

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

Product:           Distributed Data Systems WebHMI
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Administrator Compromise        -- Remote/Unauthenticated
                   Execute Arbitrary Code/Commands -- Remote/Unauthenticated
                   Unauthorised Access             -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-43936 CVE-2021-43931 

Original Bulletin: 
   https://us-cert.cisa.gov/ics/advisories/icsa-21-336-03

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ICS Advisory (ICSA-21-336-03)

Distributed Data Systems WebHMI

Original release date: December 02, 2021

Legal Notice

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1. EXECUTIVE SUMMARY

  o CVSS v3 10.0
  o ATTENTION: Exploitable remotely/low attack complexity
  o Vendor: Distributed Data Systems
  o Equipment: WebHMI
  o 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:

  o 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

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

3.4 RESEARCHER

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

4. MITIGATIONS

Distributed Data Systems recommends:

  o 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:

  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.

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