Multiple Vulnerabilities in Distributed Data Systems WebHMI Could Allow for Arbitrary Code Execution

Multiple vulnerabilities have been discovered in Distributed Data Systems WebHMI, the most severe of which could allow for arbitrary code execution. Distributed Data Systems WebHMI is a SCADA system with a built-in web server that allows you to monitor and control any automation system on the local network and via the Internet from your computer and mobile devices. Successful exploitation of the most severe of these vulnerabilities could allow an administrator account login without password authentication and remote code execution with root privileges. Depending on the privileges associated with this system, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If this system has been configured to have fewer user rights, exploitation of these vulnerabilities could have less impact than if it was configured with administrative rights.

There are currently no reports of these vulnerabilities being exploited in the wild.

Multiple vulnerabilities has been discovered in Distributed Data Systems WebHMI, the most severe of which could allow for arbitrary code execution. The vulnerabilities affect an unknown code block of the component Portal and are as follows:

• An Improper Authentication vulnerability exists due to a separate weakness primary to the authentication error. A remote attacker can bypass authentication process and gain unauthorized access to the application. (CVE-2021-43931)
• An Arbitrary File Upload vulnerability exists due to insufficient validation of file during file upload. A remote attacker can upload a malicious file and execute it on the server. (CVE-2021-43936)

Successful exploitation of the most severe of these vulnerabilities could allow an administrator account login without password authentication and arbitrary code execution with root privileges. Depending on the privileges associated with this system, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If this application has been configured to have fewer user rights on the system, exploitation of these vulnerabilities could have less impact than if it was configured with administrative rights.

We recommend the following actions be taken:

• 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.
• Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
• Apply the Principle of Least Privilege to all systems and services.