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AUSCERT External Security Bulletin Redistribution
ESB-2019.1910
Advisory (ICSA-19-148-01) Emerson Ovation OCR400 Controller
29 May 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Emerson Ovation OCR400 Controller
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Existing Account
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2019-10967 CVE-2019-10965
Original Bulletin:
https://ics-cert.us-cert.gov/advisories/ICSA-19-148-01
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Advisory (ICSA-19-148-01)
Emerson Ovation OCR400 Controller
Original release date: May 28, 2019
Legal Notice
All information products included in http://ics-cert.us-cert.gov are
provided"as is" for informational purposes only. The Department of Homeland
Security (DHS) does not provide any warranties of any kind regarding any
information contained within. DHS does not endorse any commercial product or
service, referenced in this product or otherwise. Further dissemination of this
product is governed by the Traffic Light Protocol (TLP) marking in the header.
For more information about TLP, see http://www.us-cert.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 6.8
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Emerson
o Equipment: Ovation OCR400 Controller
o Vulnerabilities: Stack-based Buffer Overflow, Heap-based Buffer Overflow
2. RISK EVALUATION
Successful exploitation of these vulnerabilities may allow privilege escalation
or remote code execution, or it may halt the controller.
For clarification, the referenced hardware is running a software version the
vendor retired in July 2015. The identified vulnerabilities exist in a
third-party embedded software version discontinued by that vendor.
In addition, the vulnerable services are disabled by default in all product
releases since 2007.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Emerson Ovation Controller OCR400, a process control
device, are affected:
o Emerson Ovation OCR400 Controller running Ovation Version 3.3.1 or earlier
These discontinued product versions include an embedded third-party FTP server,
which is the vulnerable component. The vulnerable version of the FTP server was
discontinued by that vendor several years ago.
3.2 VULNERABILITY OVERVIEW
3.2.1 STACK-BASED BUFFER OVERFLOW CWE-121
A stack-based buffer overflow vulnerability has been identified in the embedded
third-party FTP server. The vulnerability involves improper handling of a long
file name from the LIST command to the FTP service, which may cause the service
to overwrite buffers, leading to remote code execution and escalation of
privileges.
CVE-2019-10967 has been assigned to this vulnerability. A CVSS v3 base score of
6.3 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:R/S:U/C:L/
I:H/A:N ).
3.2.2 HEAP-BASED BUFFER OVERFLOW CWE-122
A heap-based buffer overflow vulnerability has been identified in the embedded
third-party FTP server. The vulnerability involves improper handling of a long
command to the FTP service, which may cause memory corruption that halts the
controller or leads to remote code execution and escalation of privileges.
CVE-2019-10965 has been assigned to this vulnerability. A CVSS v3 base score of
6.8 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:R/S:U/C:L/
I:H/A:L ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Electrical (Power Generation), Water and
Wastewater
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: United States
3.4 RESEARCHER
VDLab, a collaboration of Venustech and Dongfang Electric Corporation (DEC),
reported these vulnerabilities to NCCIC.
4. MITIGATIONS
Emerson is issuing a notice to its customer base with mitigation
recommendations, encouraging users with this older software to upgrade to a
more current version supported by Emerson and the third-party vendor.
For users with installations of the affected versions, Emerson recommends
following the instructions outlined in Step 1 and Step 2 (below) to determine
whether communication services (including FTP) have been enabled. If
communication services have been enabled, Emerson recommends users return FTP
services to their default (disabled) state as soon as is practical. If users
are unable to make controller changes or disable communication services per the
instructions below, they are strongly encouraged to restrict FTP communications
to the required database and controller drops only.
Review Ovation Software and Hardware
Step 1 - Check the Ovation Controller Type
In Ovation Developer Studio, right-click on each controller object, select
"Open" and review the "Controller Type" listed. Alternately, run a System
Registration report and verify the "Model" for each controller.
o OCR400: The controller is potentially affected; continue with Step 2
(below)
o OCR161: The controller is not affected by the vulnerabilities detailed in
this advisory, and can be disregarded
Step 2 - Check the Ovation Software Version
Ovation v3.0.4 and older
FTP services cannot be disabled using the Communications Services configuration
detailed below. Emerson recommends users of retired systems, including Ovation
v3.3.1 and older, consider upgrading to a more current version in which these
issues do not exist.
However, separate mitigation involving network configuration may still be
possible. Please refer to the "Review Ovation Highway Switch Configuration"
section (below).
Ovation v3.1.0 - v3.3.1
Follow the "Determine Current State of Communications Services" (below).
Ovation v3.5.0 and Newer
FTP communications services cannot be enabled. This advisory does not apply to
those versions.
Determine Current State of Communication Services
Two methods exist for checking the current state of controller communication
services:
1. Ovation Developer Studio
2. Controller Diagnostics application
Method 1 - Use Ovation Developer Studio to determine the state and modify as
needed
The steps necessary to review and/or modify communications services settings
can be found in Section 5.10.1 of the Developer Studio User Guide for Ovation
3.3.1 (PWS_005981), which is available on the Ovation Users' Group website:
www.ovationusers.com (this website requires registration).
Method 2 - Use Controller Diagnostics to determine the state and modify as
needed
1. Open the Controller Diagnostic application on an Ovation HMI.
2. Select a drop pair by double-clicking on it in the lower-left tree.
3. In the upper-left menu, verify the "Comm Services" section is set to
"Disabled" for both the primary and secondary controllers.
4. If "Enabled," left-click on the object to activate the drop-down menu and
select "Disabled."
Review Ovation Highway Switch Configurations
Systems using Cisco 2960 and/or 3750 switches on the Ovation Highway may be
able to limit FTP communications (as well as telnet, rlogin, and SSH) using
access control lists (ACLs). Please refer to the whitepaper "Enabling TELNET,
SSH, RLOGIN & FTP Blocking on Ovation Switches," which is available at
www.ovationusers.com (Support and Security | Security | Network Whitepapers).
Ovation Contact Information
Ovation users with questions or concerns regarding the impact of these
vulnerabilities on Ovation should contact the Ovation-CERT via email at
OvationCERT@emerson.com or by phone at 1-800-445-9723, Option 3.
NCCIC recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
o Minimize network exposure for all control system devices and/or systems,
and ensure that they are not accessible from the Internet .
o Locate control system networks and remote devices behind firewalls, and
isolate them from the business network.
o 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.
NCCIC reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
NCCIC also provides a section for control systems security recommended
practices on the ICS-CERT web page. 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-CERT website 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 NCCIC for tracking
and correlation against other incidents.
NCCIC also recommends that users take the following measures to protect
themselves from social engineering attacks:
o Do not click web links or open unsolicited attachments in email messages.
o Refer to Recognizing and Avoiding Email Scams for more information on
avoiding email scams.
o Refer to Avoiding Social Engineering and Phishing Attacks for more
information on social engineering attacks.
No known public exploits specifically target these vulnerabilities.
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