1. EXECUTIVE SUMMARY

CVSS v3 7.5
ATTENTION: Exploitable remotely/low attack complexity
Vendor: PTC
Equipment: KEPServerEX
Vulnerability: Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of this vulnerability could result in the affected device crashing.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of KEPServerEX, an industrial automation data concentrator and device manager, are affected:

KEPServerEX: Versions 6.0 to 6.14.263

3.2 VULNERABILITY OVERVIEW

3.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400

PTC’s 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 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

Claroty Team82 reported this vulnerability to PTC and CISA.

4. MITIGATIONS

PTC wishes to inform users that the attack vector leveraged during the research involved an un-authenticated OPC UA Client. Standard controls available in the product and outlined in the Secure Deployment guide are sufficient to mitigate this vulnerability. Please refer to this article for additional details.

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 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 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 its 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 at 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.

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 exploits specifically target this vulnerability.