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1. EXECUTIVE SUMMARY

2. RISK EVALUATION

Successful exploitation of this vulnerability could cause the device to crash.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Rockwell Automation’s KEPServer are affected:

3.2 Vulnerability Overview

3.2.1 Uncontrolled Resource Consumption CWE-400

KEPServerEX Versions 6.0 to 6.14.263 are vulnerable to being made to read a recursively defined object that leads to uncontrolled resource consumption. KEPServerEX uses OPC UA, a protocol which defines various object types that can be nested to create complex arrays. It does not implement a check to see if such an object is recursively defined, so an attack could send a maliciously created message that the decoder would try to decode until the stack overflowed and the device crashed.

CVE-2023-3825 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

3.4 RESEARCHER

Rockwell Automation reported this vulnerability to CISA.

4. MITIGATIONS

Rockwell automation recommends that users upgrade to KEPServer Version 6.15 or higher.

Rockwell Automation also encourages users using the affected software to apply the following risk mitigations, if possible.

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

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:

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

5. UPDATE HISTORY

Support Ends for Windows 10 22H2, Windows Server 2012 R2, Exchange 2013, Office 2016