Schweitzer Engineering Laboratories SEL

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1. EXECUTIVE SUMMARY

• CVSS v4 5.9
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Schweitzer Engineering Laboratories
• Equipment: SEL 700 series relays
• Vulnerability: Inclusion of Undocumented Features

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to make modifications or cause a denial-of-service condition.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Schweitzer Engineering Laboratories products are affected:

• SEL-700BT Motor Bus Transfer Relay: R301-V0 up to but not including R301-V6
• SEL-700BT Motor Bus Transfer Relay: R302-V0 up to but not including R302-V1
• SEL-700G Generator Protection Relay: R100-V0 up to but not including R301-V6
• SEL-700G Generator Protection Relay: R302-V0 up to but not including R302-V1
• SEL-710-5 Motor Protection Relay: R100-V0 up to but not including R302-V1
• SEL-751 Feeder Protection Relay: R101-V0 up to but not including R302-V3
• SEL-751 Feeder Protection Relay: R400-V0 up to but not including R400-V2
• SEL-787-2/-3/-4 Transformer Protection Relay: R100-V0 up to but not including R302-V1
• SEL-787Z High-Impedance Differential Relay: R302-V0 up to but not including R302-V3

3.2 Vulnerability Overview

3.2.1 INCLUSION OF UNDOCUMENTED FEATURES CWE-1242

Inclusion of undocumented features vulnerability accessible when logged on with a privileged access level on the following Schweitzer Engineering Laboratories relays could allow the relay to behave unpredictably.

CVE-2024-2103 has been assigned to this vulnerability. A CVSS v3.1 base score of 6.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2024-2103. A base score of 5.9 has been calculated; the CVSS vector string is (CVSS4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Energy
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

An anonymous researcher reported this vulnerability to CISA.

4. MITIGATIONS

Schweitzer Engineering Laboratories recommends updating to the latest versions:

• SEL-700BT Motor Bus Transfer Relay: R301-V6
• SEL-700BT Motor Bus Transfer Relay: R302-V1
• SEL-700G Generator Protection Relay: R301-V6
• SEL-700G Generator Protection Relay: R302-V1
• SEL-710-5 Motor Protection Relay: R302-V0
• SEL-751 Feeder Protection Relay: R302-V3
• SEL-751 Feeder Protection Relay: R400-V2
• SEL-787-2/-3/-4 Transformer Protection Relay: R302-V1
• SEL-787Z High-Impedance Differential Relay: R302-V3

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, such as:

• Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
• Locate control system networks and remote devices behind firewalls and isolate them from business networks.
• When remote access is required, use more 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 VPNs are only as secure as the 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 cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.

5. UPDATE HISTORY

• April 4, 2024: Initial Publication

• Schweitzer Engineering Laboratories