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AUSCERT External Security Bulletin Redistribution
ESB-2016.0262
Rockwell Automation MicroLogix 1100 PLC Overflow Vulnerability
1 February 2016
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AusCERT Security Bulletin Summary
---------------------------------
Product: Rockwell Automation MicroLogix 1100 PLC
Publisher: US-CERT
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2016-0868
Original Bulletin:
https://ics-cert.us-cert.gov/advisories/ICSA-16-026-02
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Advisory (ICSA-16-026-02)
Rockwell Automation MicroLogix 1100 PLC Overflow Vulnerability
Original release date: January 26, 2016
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/.
OVERVIEW
David Atch of CyberX has identified a stack-based buffer overflow
vulnerability in Rockwell Automations Allen-Bradley MicroLogix 1100
programmable logic controller (PLC) systems. Rockwell Automation has produced
a new firmware version to mitigate this vulnerability.
This vulnerability could be exploited remotely.
AFFECTED PRODUCTS
The following Allen-Bradley MicroLogix 1100 controller platforms are affected:
1763-L16AWA, Series B, Version 15.000 and prior versions,
1763-L16BBB, Series B, Version 15.000 and prior versions,
1763-L16BWA, Series B, Version 15.000 and prior versions,
1763-L16DWD, Series B, Version 15.000 and prior versions,
1763-L16AWA, Series A, Version 15.000 and prior versions,
1763-L16BBB, Series A, Version 15.000 and prior versions,
1763-L16BWA, Series A, Version 15.000 and prior versions, and
1763-L16DWD, Series A, Version 15.000 and prior versions.
IMPACT
Successful exploitation of the stack-based buffer overflow vulnerability may
allow an attacker to remotely execute arbitrary code on the affected device.
Impact to individual organizations depends on many factors that are unique to
each organization. NCCIC/ICS-CERT recommends that organizations evaluate the
impact of this vulnerability based on their operational environment,
architecture, and product implementation.
BACKGROUND
Rockwell Automation, which is a US-based company, provides industrial
automation control and information products worldwide across a wide range of
industries.
The affected products, Allen-Bradley MicroLogix 1100, are PLCs. According to
Rockwell Automation, these products are deployed across several sectors,
including Chemical, Critical Manufacturing, Food and Agriculture, Water and
Wastewater Systems, and others. Rockwell Automation estimates that these
products are used worldwide.
VULNERABILITY CHARACTERIZATION
VULNERABILITY OVERVIEW
STACK-BASED BUFFER OVERFLOW[a]
A stack-based buffer overflow vulnerability exists in a vulnerable function
that may allow remote code execution when the device receives a malicious web
request.
CVE-2016-0868[b] has been assigned to this vulnerability. A CVSS v3 base score
of 9.8 has been assigned; the CVSS vector string is
(AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).[c]
VULNERABILITY DETAILS
EXPLOITABILITY
This vulnerability could be exploited remotely.
EXISTENCE OF EXPLOIT
No known public exploits specifically target this vulnerability.
DIFFICULTY
An attacker with a low skill would be able to exploit this vulnerability.
MITIGATION
Rockwell Automation has addressed the stack-based buffer overflow
vulnerability in the Allen-Bradley MicroLogix 1100 controller, hardware Series
B, in firmware Version 15.002. The identified vulnerability is not addressed
in the Allen-Bradley MicroLogix 1100 controller, hardware Series A. Rockwell
Automation recommends that asset owners using Series A controllers should
implement the appropriate mitigations, which are discussed below.
Rockwell Automations new firmware version for the MicroLogix 1100 controller,
hardware Series B, firmware Version 15.002, is available at the following URL:
http://compatibility.rockwellautomation.com/Pages/MultiProductDownload.aspx?famID=30
(link is external)
Rockwell Automations security notification is available at the following URL,
with a valid account:
https://rockwellautomation.custhelp.com/app/answers/detail/a_id/765050 (link
is external)
Rockwell Automation recommends evaluating the impact of the identified
vulnerability within the host environment, and applying the following
suggested mitigations, which are applicable.
Update supported products with appropriate firmware updates.
Disable the web server on the MicroLogix 1100, as it is enabled by default.
See the knowledgebase article, KB: 732398, for detailed instructions on
disabling the web server for each controller platform. The KB: 732398 is
available at the following URL, with a valid account:
https://rockwellautomation.custhelp.com/app/answers/detail/a_id/732398 (link
is external)
Set the key switch to RUN to prohibit re-enabling of the web server via
RSLogix 500.
Rockwell Automation recommends subscribing to the Security Advisory Index
(KB54102), which provides the most up-to-date information about security
matters that affect Rockwell Automation products. The Knowledgebase article is
available at the following URL, with a valid account:
https://rockwellautomation.custhelp.com/app/answers/detail/a_id/54102 (link is
external)
ICS-CERT recommends that users take defensive measures to minimize the risk of
exploitation of the identified 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.
ICS-CERT reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
ICS-CERT also provides a section for control systems security recommended
practices on the ICS-CERT web page at:
http://ics-cert.us-cert.gov/content/recommended-practices. 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 in the ICS-CERT Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
Strategies, that is available for download from the ICS-CERT web site
(http://ics-cert.us-cert.gov/).
Organizations observing any suspected malicious activity should follow their
established internal procedures and report their findings to ICS-CERT for
tracking and correlation against other incidents.
a. CWE-121: Stack-based Buffer Overflow,
http://cwe.mitre.org/data/definitions/121.html, web site last accessed January
26, 2016.
b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-0868, NIST
uses this advisory to create the CVE web site report. This web site will be
active sometime after publication of this advisory.
c. CVSS Calculator,
https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S...,
web site last accessed January 26, 2016.
Contact Information
For any questions related to this report, please contact ICS-CERT at:
Email: ics-cert@hq.dhs.gov (link sends e-mail)
Toll Free: 1-877-776-7585
International Callers: (208) 526-0900
For industrial control systems security information and incident reporting:
http://ics-cert.us-cert.gov
ICS-CERT continuously strives to improve its products and services. You can
help by choosing one of the links below to provide feedback about this
product.
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