EFACEC BCU 500

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1. EXECUTIVE SUMMARY

• CVSS v3 9.6
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: EFACEC
• Equipment: BCU 500
• Vulnerabilities: Uncontrolled Resource Consumption, Cross-site Request Forgery

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to cause a denial-of-service condition on the affected product or compromise the web application through a cross-site request forgery (CSRF) vulnerability.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following version of EFACEC BCU 500, an automation and control IED, is affected:

• BCU 500: version 4.07

3.2 Vulnerability Overview

3.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400

Through the exploitation of active user sessions, an attacker could send custom requests to cause a denial-of-service condition on the device.

CVE-2023-50707 has been assigned to this vulnerability. A CVSS v3 base score of 9.6 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H).

3.2.2 CROSS-SITE REQUEST FORGERY (CSRF) CWE-352

A successful CSRF attack could force the user to perform state changing requests on the application. If the victim is an administrative account, a CSRF attack could compromise the entire web application.

CVE-2023-6689 has been assigned to this vulnerability. A CVSS v3 base score of 8.2 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Energy, Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Multiple
• COMPANY HEADQUARTERS LOCATION: Portugal

3.4 RESEARCHER

Aarón Flecha Menéndez of S21sec reported this vulnerability to CISA.

4. MITIGATIONS

EFACEC released BCU 500 versions 4.08 to mitigate this vulnerability.

For more information, contact EFACEC support.

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 isolating 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 VPN is 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.

CISA also recommends users take the following measures to protect themselves from social engineering attacks:

• Do not click web links or open attachments in unsolicited email messages.
• Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
• Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.

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

5. UPDATE HISTORY

• December 19, 2023: Initial Publication