1. EXECUTIVE SUMMARY

CVSS v3 7.1
ATTENTION: Low attack complexity
Vendor: Rockwell Automation
Equipment: FactoryTalk Edge Gateway
Vulnerability: Out-of-bounds Read

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow a local user to cause the program to crash, causing a denial of service.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Rockwell Automation reports this vulnerability affects the following FactoryTalk Edge Gateway products:

FactoryTalk Edge Gateway: v1.3

3.2 VULNERABILITY OVERVIEW

3.2.1 OUT-OF-BOUNDS READ CWE-125

An out of bounds array read vulnerability was fixed in the apr_time_exp*() function in the Apache Portable Runtime v1.6.3 (CVE-2017-12613). The fix for this issue was not carried forward to the APR 1.7.x branch, and hence version 1.7.0 regressed compared to 1.6.3 and is vulnerable to the same issue.

CVE-2021-35940 has been assigned to this vulnerability. A CVSS v3 base score of 7.1 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H).

3.3 BACKGROUND

CRITICAL INFRASTRUCTURE SECTORS: Food and Agriculture, Transportation Systems, Water and Wastewater Systems
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

Rockwell Automation reported this vulnerability to CISA.

4. MITIGATIONS

Rockwell Automation encourages users of the affected software to apply the risk mitigation below, if possible. Additionally, they encourage users to implement their suggested security best practices to minimize the risk.

Update to v1.4
Security Best Practices

Please see the Rockwell Automation publication regarding this issue for more information.

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. This vulnerability is not exploitable remotely.