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AUSCERT External Security Bulletin Redistribution
ESB-2014.0447
Schneider Electric OPC Factory Server Buffer Overflow
7 April 2014
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AusCERT Security Bulletin Summary
---------------------------------
Product: Schneider Electric OPC Factory Server
Publisher: US-CERT
Operating System: Windows
Impact/Access: Denial of Service -- Unknown/Unspecified
Resolution: Patch/Upgrade
CVE Names: CVE-2014-0789
Original Bulletin:
http://ics-cert.us-cert.gov/advisories/ICSA-14-093-01
Comment: Exploits that target this vulnerability are publicly available.
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Advisory (ICSA-14-093-01)
Schneider Electric OPC Factory Server Buffer Overflow
Original release date: April 03, 2014
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
Researcher Wei Gao, formerly of IXIA, has identified a buffer overflow
vulnerability in the Schneider Electric OPC Factory Server (OFS) application.
Schneider Electric has produced a patch that mitigates this vulnerability.
Wei Gao has tested the patch to validate that it resolves the vulnerability.
This vulnerability could be exploited remotely.
AFFECTED PRODUCTS
Schneider Electric reports that the vulnerability affects the following
versions of OFS:
- - TLXCDSUOFS33 – V3.5 and previous,
- - TLXCDSTOFS33 – V3.5 and previous,
- - TLXCDLUOFS33 – V3.5 and previous,
- - TLXCDLTOFS33 – V3.5 and previous, and
- - TLXCDLFOFS33 – V3.5 and previous.
IMPACT
A successful exploitation will cause the server to reboot resulting in a
denial of service.
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
Schneider Electric corporate headquarters is located in Paris, France, and
maintains offices in more than 100 countries worldwide.
These products are industrial active energy management control products,
deployed across several sectors including the Energy, Water and Wastewater
Systems, Commercial Facilities, Government Facilities, Food and Agriculture,
and Transportation Systems. Schneider Electric estimates that these products
are used primarily in the United States and North America.
VULNERABILITY CHARACTERIZATION
VULNERABILITY OVERVIEW
BUFFER OVERFLOW [a]
Incorrect parsing in the OPC Automation 2.0 Server Object (ActiveX) can result
in a buffer overflow error. The vulnerability is caused by parsing long
arguments in functions.
CVE-2014-0789 [b] has been assigned to this vulnerability. A CVSS v2 base
score of 5.0 has been assigned; the CVSS vector string is
(AV:N/AC:L/Au:N/C:N/I:N/A:P). [c]
VULNERABILITY DETAILS
EXPLOITABILITY
This vulnerability could be exploited remotely.
EXISTENCE OF EXPLOIT
Exploits that target this vulnerability are publicly available.
DIFFICULTY
An attacker with a low skill would be able to exploit this vulnerability.
MITIGATION
Schneider Electric has developed a patch to resolve this issue. In order to
patch the installation in the field, install OFS V3.5SP1, available on
Schneider Electric’s web site at the following URL:
http://www.schneider-electric.com/download/WW/EN/results/0/0/8336568-OPC-Factory-Server/0/?showAsIframe=true
OFS V3.5SP1 includes a patched version of the OLE2T macro from Microsoft to
resolve the issue.
For more information regarding this issue, please see the security
announcements affecting the OPC Factory Server on Schneider Electric’s web
site at the following URL:
http://www2.schneider-electric.com/sites/corporate/en/support/cybersecurity/cybersecurity.page
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 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 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 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. ICS-CERT reminds organizations to perform proper
impact analysis and risk assessment prior to deploying defensive measures.
Additional mitigation guidance and recommended practices are publicly
available in the ICS‑CERT Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion 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-122: Heap-based Buffer Overflow, http://cwe.mitre.org/data/definitions/122.html,
web site last accessed April 03, 2014.
[b]. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-0789,
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, http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:L/Au:N/C:N/I:N/A:P,
web site last accessed April 03, 2014.
Contact Information
For any questions related to this report, please contact ICS-CERT at:
Email: ics-cert@hq.dhs.gov
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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