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AUSCERT External Security Bulletin Redistribution
ESB-2016.2335
Beckhoff Embedded PC Images and TwinCAT Components Vulnerabilities
6 October 2016
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AusCERT Security Bulletin Summary
---------------------------------
Product: Beckhoff Embedded PC Images
TwinCAT Components
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Access Privileged Data -- Remote/Unauthenticated
Resolution: Mitigation
CVE Names: CVE-2014-5415 CVE-2014-5414
Original Bulletin:
http://ics-cert.us-cert.gov/advisories/ICSA-16-278-02
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Advisory (ICSA-16-278-02)
Beckhoff Embedded PC Images and TwinCAT Components Vulnerabilities
Original release date: October 04, 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
Marko Schuba from FH Aachen University of Applied Sciences has identified
vulnerabilities in Beckhoffs Embedded PC Images and TwinCAT Components. He
published them and reported them to Beckhoff afterward. In 2014, Beckhoff
produced a new build and security advisories with instructions to mitigate
these vulnerabilities.
These vulnerabilities could be exploited remotely.
AFFECTED PRODUCTS
Beckhoff reports that the vulnerabilities may affect the following products:
- - All Beckhoff Embedded PC Images with a creation date prior to October 22,
2014, and
- - All TwinCAT Components featuring Automation Device Specification (ADS)
communication.
IMPACT
If used without proper protection, an attacker may misuse those services to
gain unauthorized access to systems or read and manipulate transmitted
information, especially passwords. Attackers may use ADS protocol to rapidly
probe a large number of user or password combinations.
Impact to individual organizations depends on many factors that are unique to
each organization. NCCIC/ICS-CERT recommends that organizations evaluate the
impact of these vulnerabilities based on their operational environment,
architecture, and product implementation.
BACKGROUND
Beckhoff is a German-based company.
Beckhoff Embedded PCs are hardware PC products meant to be installed in
control cabinets and be configured to function in many different ways in an
industrial control system. Beckhoff TwinCAT is a software product that can
allow a PC to function as a real-time controller. According to Beckhoff, these
products are deployed across several sectors including Critical Manufacturing,
Energy, and Water and Wastewater Systems, and others. Beckhoff estimates that
these products are used worldwide.
VULNERABILITY CHARACTERIZATION
VULNERABILITY OVERVIEW
IMPROPER RESTRICTION OF EXCESSIVE AUTHENTICATION ATTEMPTS [a]
Attackers may use ADS protocol to rapidly probe a large number of user or
password combinations.
CVE-2014-5414 [b] has been assigned to this vulnerability. A CVSS v3 base score
of 9.1 has been calculated; the CVSS vector string is
(AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N). [c]
EXPOSED DANGEROUS METHOD OR FUNCTION [d]
In versions older than October 22, 2014, Beckhoff Images for Embedded PCs are
delivered with the Windows CE Remote Configuration Tool reachable, enabled CE
Remote Display service, and enabled telnet service. Use of these services is
recommended only in trusted networks. If used without proper protection, an
attacker may misuse those services to gain unauthorized access to systems or
read and manipulate transmitted information, especially passwords.
Precondition of the exploitation of those services is that the attacker has
access to the services at the corresponding network ports (TCP 80/987/23).
This implies that the services are running.
CVE-2014-5415 [e] has been assigned to this vulnerability. A CVSS v3 base score
of 9.1 has been calculated; the CVSS vector string is
(AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N). [f]
VULNERABILITY DETAILS
EXPLOITABILITY
These vulnerabilities could be exploited remotely.
EXISTENCE OF EXPLOIT
No known public exploits specifically target these vulnerabilities.
DIFFICULTY
An attacker with a low skill would be able to exploit these vulnerabilities.
MITIGATION
Beckhoff recommends in their IPC Security Manual
(https://download.beckhoff.com/download/Document/ipc/industrial-pc/ipc_security_en.pdf
(link is external)) to use network and software firewalls to block all network
ports except the ones that are needed. Beckhoff also recommends that default
passwords be changed during commissioning before connecting systems to the
network.
In their advisories (Advisory 2014-001, [g] Advisory 2014-002, [h] Advisory
2014-003, [i] which were published November 17, 2014) for these issues, Beckhoff
also recommends the following mitigation solutions:
- - Update images to build October 22, 2014, or newer, which solve these
problems by disabling the services by default.
- - Disable the Windows CE Remote Configuration Tool by deleting the subtree
/remoteadmin. The configuration of the web server paths can be found in the
Windows registry at the path HKEY_LOCAL_MACHINE\COMM\HTTPD\VROOTS\.
- - Disable startup of CE Remote Display service (cerdisp.exe) with deleting the
registry key containing the CeRDisp.exe [-HKEY_LOCAL_MACHINE\init\Launch90].
- - Disable telnet by setting the registry key
[HKEY_LOCAL_MACHINE\Services\TELNETD\Flags] to dword: 4
- - Restrict ADS communication to trusted networks only.
ICS-CERT recommends that users take defensive measures to minimize the risk of
exploitation of these vulnerabilities. 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. 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 ICSCERT 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.
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-307: Improper Restriction of Excessive Authentication Attempts,
https://cwe.mitre.org/data/definitions/307.html, web site last accessed
October 04, 2016.
b. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-5414, 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 October 04, 2016.
d. CWE-749: Exposed Dangerous Method or Function,
https://cwe.mitre.org/data/definitions/749.html, web site last accessed
October 04, 2016.
e. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-5415, NIST
uses this advisory to create the CVE web site report. This web site will be
active sometime after publication of this advisory.
f. 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 October 04, 2016.
g. Advisory 2014-001: Potential misuse of several administrative services,
http://ftp.beckhoff.com/download/document/ipc/industrial-pc/advisory-201...
(link is external), web site last accessed October 04, 2016.
h. Advisory 2014-002: ADS communication port allows password bruteforce,
http://ftp.beckhoff.com/download/document/ipc/industrial-pc/advisory-201...
(link is external), web site last accessed October 04, 2016.
i. Advisory2014-003: Recommendation to change default passwords,
http://ftp.beckhoff.com/download/document/ipc/industrial-pc/advisory-201...
(link is external), web site last accessed October 04, 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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