-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2014.1403
  Advisory (ICSA-14-226-01) Siemens SIMATIC S7-1500 CPU Denial of Service
                              18 August 2014

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Siemens SIMATIC S7-1500 CPU
Publisher:         US-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2014-5074  

Original Bulletin: 
   https://ics-cert.us-cert.gov//advisories/ICSA-14-226-01

- --------------------------BEGIN INCLUDED TEXT--------------------

Advisory (ICSA-14-226-01) Siemens SIMATIC S7-1500 CPU Denial of Service 
Original release date: August 14, 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

Arnaud Ebalard from Agence Nationale de la Scurit des Systmes dInformation 
(ANSSI) has reported a denial-of-service (DoS) vulnerability in Siemens 
SIMATIC S7-1500 CPU. Siemens produced a new firmware version that mitigates 
this vulnerability and then reported it to NCCIC/ICS-CERT.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

The following Siemens SIMATIC S7-1500 CPU versions are affected:

    SIMATIC S7-1500 CPU all versions before V1.6

IMPACT

A successful exploit of this vulnerability will cause the CPU to automatically
restart and remain in the STOP mode. The CPU would then need to be manually 
put into the RUN mode to restore operations.

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

Siemens is a multinational company headquartered in Munich, Germany.

Products in the Siemens SIMATIC S7-1500 PLC family have been designed for 
discrete and continuous control in industrial environments such as 
manufacturing, food and beverages, and chemical industries worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

NUMERIC ERRORS [a]

Specially crafted TCP packets could cause a DoS of the device if sent in a 
specific order.

CVE-2014-5074 [b] has been assigned to this vulnerability. A CVSS v2 base 
score of 7.1 has been assigned; the CVSS vector string is 
AV:N/AC:M/Au:N/C:N/I:N/A:C. [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 moderate skill would be able to exploit this vulnerability.

MITIGATION

The firmware update for S7-1500 V1.6 can be obtained at the following location
on the Siemens web site:

http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=98164677&caller=view

Siemens recommends running the affected software components in a protected 
network environment and to configure the environment according to operational
guidelines. [d]

For more information regarding this issue (SSA-310688) or any other security 
issue involving Siemens products, please see the Siemens ProductCERT security
advisory page at:

www.siemens.com/cert/advisories.

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 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 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 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 
(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-189: Numeric Errors , 
http://cwe.mitre.org/data/definitions/189.html, web site last accessed August
13, 2014. 

b. NVD, 
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-5074, 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:M/Au:N/C:N/I:N/A:C, web
site last accessed August 13, 2014. 

d. Operational Guidelines for Industrial Security, 
http://www.industry.siemens.com/topics/global/en/industrial-security/Doc..., 
web site last accessed August 13, 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.

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        http://www.auscert.org.au/render.html?cid=1980

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967

iQIVAwUBU/Fw6xLndAQH1ShLAQIq7RAApnPPLKGfKM8rJwPjiAgB2s2v071wxtQy
+LM9yY5SzRVBEnrmUdpYHV/sUvatbY4zoN0bQ5j6lGX2Fuha+2Em4tEkRUQZTqqz
5xoUNqoJHlZyJ1/UeqrhQWPp1cw7ibCSwzXeD5MPO8jSrY5xPSVorXU537+BAArz
Lkyh6z0ZvjY42rpP99ibQCBOmA1bw5fURAMpsjJFen06ph02nXSNfxrDRl8+obdT
NjCacf9W8SRKuNgHHbzQ8hN42WJ+m2d+IrOmmzvW18FdILblj4eiBNfaYnx1yHPi
Gsau6Dp/KbDXm4FeTAlGWAmMQ6amf3gzDuw1ZiM8gI4eNABJHiZQtmRUbIyjZY31
StiXqfWCsFHZ/PwxWPozxUcXs6dcmhaOJyCbW7KElahOWViIdtEOzOnWpRvA1RDk
1dgr8W0n4PxTWN5+SSkprqympFi46hgSA4FChjQxYR6MwZ79U/L0X3xbTif/dJ9W
iA2sHPeTg6s7d10rnU6yHhb1A8428m40M+W0/HiJCKP8BME6k4RD5vYUTW1UAb9z
i233FiGlc67MrixVbQ5esX6TKWcGp03e6Z6EBQaZofHnqwlEaI6nshW+8L8aP0fg
NFOg4m52E0vtotN90o6UcJzoqzWAk9Sf27UxByRwvZ6BGqIlCZUdPvA5IMwc/0aQ
e+7RxEA3Cig=
=o3du
-----END PGP SIGNATURE-----