Hirschmann Automation and Control HiOS and HiSecOS Products

1. EXECUTIVE SUMMARY

• CVSS v3 9.8 *ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: Hirschmann Automation and Control GmbH, a division of Belden Inc.
• Equipment: HiOS, HiSecOS
• Vulnerability: Classic Buffer Overflow

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an unauthenticated, remote attacker to overflow a buffer and fully compromise the device.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following devices using HiOS Version 07.0.02 and lower are affected:

• RSP, RSPE, RSPS, RSPL, MSP, EES, EES, EESX, GRS, OS, RED

The following devices using HiSecOS Version 03.2.00 and lower are affected:

• EAGLE20/30

3.2 VULNERABILITY OVERVIEW

3.2.1 BUFFER COPY WITHOUT CHECKING SIZE OF INPUT (‘CLASSIC BUFFER OVERFLOW’) CWE-120

The vulnerability is due to improper parsing of URL arguments. An attacker could exploit this vulnerability by specially crafting HTTP requests to overflow an internal buffer.

CVE-2020-6994 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).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Information Technology
• **COUNTRIES/AREAS DEPLOYED:**Worldwide
• **COMPANY HEADQUARTERS LOCATION:**United States

3.4 RESEARCHER

Sebastian Krause and Toralf Gimpel of GAI NetConsult GmbH reported this vulnerability to Hirschmann.

4. MITIGATIONS

Hirschmann recommends updating HiOS products to Version 07.0.03 or higher and HiSecOS products to Version 03.3.00 or higher.

Hirschmann also recommends, as a workaround, users either use the “IP Access Restriction” feature to restrict HTTP and HTTPS to trusted IP addresses, or disable the HTTP and HTTPS server.

For more information regarding this vulnerability and the associated mitigations, please see Belden security bulletin number BSECV-2020-01.

For additional resources, please go to <https://www.belden.com/security&gt;.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• 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 that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that 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 us-cert.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.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 this vulnerability.