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AUSCERT External Security Bulletin Redistribution
ESB-2012.1161
ICSA-12-342-01 ROCKWELL ALLEN-BRADLEY MICROLOGIX, SLC 500,
AND PLC-5 FAULT GENERATION VULNERABILITY
10 December 2012
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AusCERT Security Bulletin Summary
---------------------------------
Product: Rockwell Automation Allen-Bradley MicroLogix
Rockwell Automation Allen-Bradley SLC 500
Rockwell Automation Allen-Bradley PLC-5
Publisher: US-CERT
Operating System: Network Appliance
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2012-4690
Original Bulletin:
http://www.us-cert.gov/control_systems/pdf/ICSA-12-342-01.pdf
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ICSA-12-342-01 ROCKWELL ALLEN-BRADLEY MICROLOGIX, SLC 500, AND PLC-5 FAULT
GENERATION VULNERABILITY
December 7, 2012
OVERVIEW
Independent researcher Matthew Luallen of CYBATI has identified a fault
generation vulnerability that can cause a denial of service (DoS) in the
Rockwell Automation Allen-Bradley MicroLogix, SLC 500, and PLC-5 controller.
Rockwell has released a notification [a] that includes mitigation strategies
for this vulnerability.
This vulnerability could be exploited remotely.
AFFECTED PRODUCTS
Rockwell Automation reports that the vulnerabilities affect the following
versions of Allen-Bradley devices:
* MicroLogix 1100 controller,
* MicroLogix 1200 controller,
* MicroLogix 1400 controller,
* MicroLogix 1500 controller,
* SLC 500 controller platform, and
* PLC-5 controller platform.
IMPACT
An attacker who exploits this vulnerability can cause a DoS in the affected
device.
Impact to individual organizations depends on many factors that are unique to
each organization. ICS-CERT recommends that organizations evaluate the impact
of this vulnerability based on their operational environment, architecture, and
product implementation.
BACKGROUND
Rockwell Automation provides industrial automation control and information
products worldwide, across a wide range of industries.
MicroLogix, SLC500, and PLC5 are programmable logic controllers (PLC) built by
Rockwell Automation.
VULNERABILITY CHARACTERIZATION
VULNERABILITY OVERVIEW
MODIFICATION OF ASSUMED-IMMUTABLE DATA [b]
When certain configuration parameters are not enabled, the affected devices are
susceptible to a remote attack. To exploit the vulnerability, the attacker
sends specially crafted messages that change specific bits in status files.
This creates a device fault, which in turn causes a DoS.
CVE-2012-4690 [c] has been assigned to this vulnerability. A CVSS v2 base score
of 8.5 has been assigned; the CVSS vector string is
(AV:N/AC:L/Au:N/C:N/ I:P/A:C). [d]
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 continues to assess the feasibility of enhancing security
features of the MicroLogix platform to directly address or mitigate associated
risk from this vulnerability. Due to technical limitations of the platform, the
viability of altering the platforms operation or adding specific product
controls to mitigate risk continues to be explored. Rockwell Automation [a]
recommends the following mitigation strategies to help reduce the likelihood of
compromise and the associated security risk. When possible, multiple strategies
should be employed simultaneously.
* If possible, change the controllers settings to the non-vulnerable state:
* SLC-500: Set the Status file to Static
* PLC-5: Enable the Passwords and Privileges feature
* Employ layered security and defense-in-depth methods in system design to
restrict and control access to individual products and control networks.
Refer to http://www.ab.com/networks/architectures.html for comprehensive
information about implementing validated architectures designed to deliver
these measures.
* Employ firewalls with ingress/egress filtering, intrusion
detection/prevention systems, and validate all configurations. Evaluate
firewall configurations to ensure other appropriate inbound and outbound
traffic is blocked.
* Block all traffic to the EtherNet/IP or other CIP protocol based devices from
outside the Manufacturing Zone by restricting or blocking access to both TCP
and UDP Port# 2222 and Port 44818 using appropriate security technology
(e.g., a firewall, UTM devices, or other security appliance).
* Restrict physical and electronic access to automation products, networks and
systems to only those individuals authorized to be in contact with control
system equipment.
* Enlist additional security expertise by engaging Rockwell Automations Network
& Security Services team for specialized, consultative services. For more
detail visit http://www.rockwellautomation.com/services/security/
ICS-CERT encourages asset owners to take additional defensive measures to
protect against this and other cybersecurity risks.
* Minimize network exposure for all control system devices. Critical devices
should not directly face the Internet or be directly exposed to areas of less
trust.
* 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 with confidentiality, integrity and two-factor authentication
controls (VPNs), recognizing that VPN is only as secure as the connected
devices.
ICS-CERT 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. [e] ICS-CERT reminds
organizations to perform proper impact analysis and risk assessment prior to
taking defensive measures.
Additional mitigation guidance and recommended practices are publicly available
in the ICS-CERT Technical Information Paper, ICS-TIP-12-146-01A - Cyber
Intrusion Mitigation Strategies, [f] that is available for download from the
ICS-CERT Web page (www.ics-cert.org).
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.
ICS-CERT CONTACT
For any questions related to this report, please contact ICS-CERT at:
Email: ics-cert@hq.dhs.gov
Toll Free: 1-877-776-7585
For industrial control systems security information and incident reporting:
www.ics-cert.org
ICS-CERT continuously strives to improve its products and services. You can
help by answering a short series of questions about this product at the
following URL: https://forms.us-cert.gov/ncsd-feedback/.
DOCUMENT FAQ
What is an ICS-CERT Advisory? An ICS-CERT Advisory is intended to provide
awareness or solicit feedback from critical infrastructure owners and operators
concerning ongoing cyber events or activity with the potential to impact
critical infrastructure computing networks.
May I edit this document to include additional information? This document may
not be edited or modified in any way by recipients nor may any markings be
removed. It may not be posted on public Web sites. All comments or questions
related to this document should be directed to ICS-CERT at ics-cert@hq.dhs.gov.
When is vulnerability attribution provided to researchers? Attribution for
vulnerability discovery is always provided to the vulnerability reporter unless
the reporter notifies ICS-CERT that they wish to remain anonymous. ICS-CERT
encourages researchers to coordinate vulnerability details before public
release. The public release of vulnerability details prior to the development
of proper mitigations may put industrial control systems and the public at
avoidable risk.
REFERENCES
a. 511407 - MicroLogix, SLC 500 and PLC-5 Controller Vulnerability,
https://rockwellautomation.custhelp.com/app/answers/detail/a_id/511407
b. CWE-471: Modification of Assumed Immutable Data,
http://cwe mitre.org/data/definitions/471.html,
Web site last accessed December 06, 2012.
c. NVD,
http://web nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-4690,
NIST uses this advisory to create the CVE Web site report. This Web site
will be active sometime after publication of this advisory.
d. CVSS Calculator,
http://nvd.nist.gov/cvss.cfm?version=2&vector=(AV:N/AC:L/Au:N/C:N/I:P/A:C,
Web site last visited December 07, 2012.
e. CSSP Recommended Practices,
http://www.us-cert.gov/control systems/practices/Recommended_Practices.html,
Web site last accessed December 06, 2012.
f. Cyber Intrusion Mitigation Strategies,
http://www.us-cert.gov/control systems/pdf/ICS-TIP-12-146-01A.pdf,
Web site last accessed December 06, 2012.
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