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AUSCERT External Security Bulletin Redistribution
ESB-2012.1208
ICSA-12-349-01 SIEMENS AUTOMATION LICENSE MANAGER
UNCONTROLLED RESOURCE CONSUMPTION
20 December 2012
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens Automation License Manager
Publisher: US-CERT
Operating System: Windows
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2012-4691
Original Bulletin:
http://www.us-cert.gov/control_systems/pdf/ICSA-12-349-01.pdf
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ICS-CERT ADVISORY
ICSA-12-349-01SIEMENS AUTOMATION LICENSE MANAGER UNCONTROLLED RESOURCE
CONSUMPTION
December 14, 2012
OVERVIEW
This advisory provides mitigation details for a vulnerability that impacts the
Siemens Automation License Manager (ALM).
Siemens ProductCERT has identified an uncontrolled resource consumption
vulnerability (a) in the Siemens ALM, which is used for license management by
various Siemens software products. Siemens has produced a software update that
fully resolves this vulnerability. Exploitation of this vulnerability would
allow loss of availability of the system.
AFFECTED PRODUCTS
All Siemens software products that include ALM version between 4.0 and 5.2 are
affected. The following Siemens product families are affected:
SIMATIC (e.g., STEP 7)
SIMATIC HMI (e.g., WinCC, WinCC flexible)
SIMATIC PCS 7
SIMOTION (e.g., Scout)
SIMATIC NET
SINAMICS (e.g., Starter)
SIMOCODE.
IMPACT
Attackers could exploit the vulnerability to cause memory leakage within the
software. This exploit could eventually lead to a crash of the application. The
DoS of the ALM could lead to a DoS of associated devices that use the ALM to
verify active licenses.
Impact to individual organizations depends on many factors that are unique to
each organization. ICS-CERT recommends that organizations evaluate the impact
of these vulnerabilities based on their operational environment, architecture,
and product implementation.
BACKGROUND
Siemens is a multinational company headquartered in Munich, Germany. Siemens
develops products mainly in the energy, transportation, and healthcare sectors.
ALM centrally manages licenses for various Siemens software products. The
products contact ALM either locally or remotely to verify their license using a
proprietary protocol. To enable this license verification, ALM listens on Port
4410/TCP by default. These products are deployed across several sectors
including energy, healthcare, and others worldwide.
VULNERABILITY CHARACTERIZATION
VULNERABILITY OVERVIEW
UNCONTROLLED RESOURCE CONSUMPTION (b)
An attacker can send maliciously crafted packets to Port 4410/TCP, which will
cause a memory leakage and uncontrolled resource consumption, leading to a DoS.
CVE-2012-4691 (c) has been assigned to this vulnerability. A CVSS v2 base score
of 7.8 has been assigned; the CVSS vector string is
(AV:N/AC:L/Au:N/C:N/I:N/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
Siemens has provided an update (e) that resolves this vulnerability. The update
can be applied to all versions of ALM starting with version 4.0. Siemens
recommends that asset owners and operators can contact Siemens customer
support(f) to acquire the update.
Siemens recommends blocking traffic to Port 4410/TCP from external and remote
connections.
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.
* 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 US-CERT Web page. Several recommended practices are available
for reading and download, including Improving Industrial Control Systems
Cybersecurity with Defense-in-Depth Strategies. (g) 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,(h) 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.
a. SSA-783261, http://www.siemens.com/corporate-technology/pool/de/forschungsfelder/siemenssecurityadvisoryssa-783261.pdf
Web site last accessed December 14, 2012.
b. CWE, http://cwe mitre.org/data/definitions/400.html, CWE-400: Uncontrolled
Resource Consumption (Resource Exhaustion), Web site last accessed December 14,
2012.
c. NVD, http://web nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-4691, 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:N/A:C)
Web site last visited December 14, 2012.
e. SSA-783261, http://www.siemens.com/corporate-technology/pool/de/forschungsfelder/siemenssecurityadvisoryssa-783261.pdf
Web site last accessed December 14, 2012.
f. Siemens Customer Support, msp.support.de@siemens.com
g. CSSP Recommended Practices, http://www.us-cert.gov/controlsystems/practices/RecommendedPractices.html
Web site last accessed December 14, 2012.
h. Cyber Intrusion Mitigation Strategies, http://www.us-cert.gov/controlsystems/pdf/ICS-TIP-12-146-01A.pdf
Web site last accessed December 14, 2012.
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.
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.
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