The vulnerabilities include inadequate encryption strength, session fixation, exposure of sensitive information to an unauthorized actor, improper input validation, unrestricted upload of file with dangerous type, insecure default variable initialization, and use of hard-coded credentials.
Successful exploitation of these remotely exploitable vulnerabilities, discovered by SCADA-X, DOE’s Cyber Testing for Resilient Industrial Control Systems (CyTRICS) program, Verve Industrial, and VuMetric, could allow an attacker to access sensitive information, reboot the UR, gain privileged access, or cause a denial-of-service condition.
GE reports the vulnerabilities affect the following UR family (B30, B90, C30, C60, C70, C95, D30, D60, F35, F60, G30, G60, L30, L60, L90, M60, N60, T35, T60) of advanced protection and control relays:
- Vulnerabilities related to SSH Support: Firmware versions 7.4x to 8.0x (CyberSentry option)
- Web server vulnerabilities: All firmware versions prior to version 8.1x
- Protection from unintended firmware upload: All firmware versions prior to 8.1x with basic security option
- Provisions to disable Factory Mode: All firmware versions prior to 8.1x with basic security option
- Access to “Last-key pressed” register: All firmware versions prior to 8.1x with basic security option
- Weakness in UR bootloader binary: All bootloader versions prior to 7.03/7.04
Please see GE publication GES-2021-004 (login required) for more information.
In one issue, prior to UR firmware Version 8.1x, UR supported various encryption and MAC algorithms for SSH communication, some of which are weak.
CVE-2016-2183 and CVE-2013-2566 are the case numbers assigned to this vulnerability, which have a CVSS v3 base score of 7.5.
In addition, prior to firmware Version 7.4x, UR supported only SSHv2. Starting from firmware Version 7.4x, UR added support to SSHv1. SSHv1 has known vulnerabilities (SSH protocol session key retrieval and insertion attack).
CVE-1999-1085 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 5.3.
Also, web server interface is supported on UR over HTTP protocol. It allows sensitive information exposure without authentication.
CVE-2021-27422 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
In another issue, UR supports web interface with read-only access. The device fails to properly validate user input, making it possible to perform cross-site scripting attacks, which may be used to send a malicious script. Also, UR Firmware web server does not perform HTML encoding of user-supplied strings.
CVE-2021-27418 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 5.3.
In addition, UR Firmware web server task does not properly handle receipt of unsupported HTTP verbs, resulting in the web server becoming temporarily unresponsive after receiving a series of unsupported HTTP requests. When unresponsive, the web server is inaccessible. By itself, this is not particularly significant as the relay remains effective in all other functionality and communication channels.
CVE-2021-27420 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 5.3.
Also, UR IED supports upgrading firmware using UR Setup configuration tool – Enervista UR Setup. This UR Setup tool validates the authenticity and integrity of firmware file before uploading the UR IED. An illegitimate user could upgrade firmware without appropriate privileges. The weakness is assessed, and mitigation is implemented in firmware Version 8.10.
CVE-2021-27428 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
In another issue, UR IED with “Basic” security variant does not allow the disabling of the “Factory Mode,” which is used for servicing the IED by a “Factory” user.
CVE-2021-27426 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 9.8.
In addition, UR shares MODBUS memory map as part of the communications guide. GE was made aware a “Last-key pressed” MODBUS register can be used to gain unauthorized information.
CVE-2021-27424 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 5.3.
Also, UR bootloader binary Version 7.00, 7.01 and 7.02 included unused hardcoded credentials. Additionally, a user with physical access to the UR IED can interrupt the boot sequence by rebooting the UR.
CVE-2021-27430 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.4.
The product sees use in the communications, critical manufacturing, energy, healthcare and public health, transportation systems, and water and wastewater systems sectors. It also sees action on a global basis.
No known public exploits specifically target these vulnerabilities. However, an attacker with low skill level could leverage the vulnerabilities.
GE recommends users with impacted firmware versions update their UR devices to UR firmware Version 8.10, or greater to resolve these vulnerabilities. GE provides additional mitigations and information about these vulnerabilities in GE Publication Number: GES-2021-004 (login required).
GE recommends protecting UR IED by using network defense-in-depth practices. This includes, but is not limited to, placing UR IED inside the control system network security perimeter, and having access controls, monitoring (such as an Intrusion Detection System), and other mitigating technologies in place.
GE recommends users refer to the UR Deployment guide for secure configuration of UR IED and system.