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             AUSCERT External Security Bulletin Redistribution

                               ESB-2015.3023
           Siemens SIMATIC Communication Processor Vulnerability
                              4 December 2015

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

Product:           Siemens SIMATIC Communication Processor devices
Publisher:         US-CERT
Operating System:  Network Appliance
Impact/Access:     Administrator Compromise -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2015-8214  

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSA-15-335-03

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Advisory (ICSA-15-335-03)

Siemens SIMATIC Communication Processor Vulnerability

Original release date: December 01, 2015

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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

Siemens has identified an authentication bypass vulnerability in Siemens 
SIMATIC Communication Processor devices CP 343-1, TIM 3V-IE, TIM 4R-IE, and CP
443-1. The vulnerability was reported directly to Siemens by Lei ChengLin 
(Z-0ne) from the Fengtai Technologies Security Research Team. Siemens has 
produced a firmware update to mitigate this vulnerability in the SIMATIC CP 
343-1 Advanced modules.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

The following Communication Processor modules, which are designed to be used 
with Siemens SIMATIC S7-300/S7-400 CPUs, are affected:

	SIMATIC CP 343-1 Advanced: All firmware versions prior to V3.0.44,

	SIMATIC CP 343-1 Lean / CP 343-1: All firmware versions,

	SIMATIC TIM 3V-IE / 3V-IE Advanced: All firmware versions,

	SIMATIC TIM 3V-IE DNP3: All firmware versions,

	SIMATIC TIM 4R-IE: All firmware versions,

	SIMATIC TIM 4R-IE DNP3: All firmware versions, and

	SIMATIC CP 443-1 / CP 443-1 Advanced: All firmware versions.

IMPACT

Successful exploitation of this vulnerability may allow unauthenticated users
to perform administrative operations on the SIMATIC Communication Processor 
under certain conditions.

Impact to individual organizations depends on many factors that are unique to
each organization. NCCIC/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.

The affected products, Siemens SIMATIC Communication Processor module 
families, are designed to enable SIMATIC S7-300/S7-400 CPUs for Ethernet or 
Telecontrol communication. Siemens estimates that these products are used 
worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

AUTHENTICATION BYPASS ISSUES [a]

Communication Processor module families may allow unauthenticated users to 
perform administrative operations on the Communication Processor if network 
access to Port 102/TCP is available and the Communication Processors 
configuration is stored on its corresponding CPUs.

CVE-2015-8214 [b] has been assigned to this vulnerability. A CVSS v3 base 
score of 9.4 has been assigned; the CVSS vector string is 
(AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H). [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 low skill would be able to exploit this vulnerability.

MITIGATION

Siemens has released a firmware update, V3.0.44, for SIMATIC CP 343-1 Advanced
modules and is working on firmware updates for the remaining affected 
products. Siemens recommends that customers update to the new firmware update,
V3.0.44, which is available at the following URL: 
https://support.industry.siemens.com/cs/ww/en/view/109480765 (link is 
external)

Siemens also recommends applying the following mitigations in the meantime:

   Activate firewall functionality on Advanced-Communication Processor
   and reject S7-communication at the perimeter port,

   Apply cell protection concept, which is described in the following URL:
   https://www.siemens.com/cert/operational-guidelines-industrial-security
   (link is external)

   Use VPN for protecting network communication between cells, and

   Apply Defense-in-Depth, which is described in the following URL: 
   http://www.industry.siemens.com/topics/global/en/industrial-security/concept/Pages/defense-in-depth.aspx
   (link is external).

Siemens has also identified the following conditions that must exist for an 
attacker to exploit the identified vulnerability: Network access to the 
affected devices, Configuration data for the CP must be stored on CPU, and 
Firewall functionality of Advanced-CPs must be turned off for Port 102/TCP.

For more information on this vulnerability and detailed instructions, please 
see Siemens Security Advisory SSA-763427 at the following location: 
http://www.siemens.com/cert/advisories (link is external)

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 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.

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-592: Authentication Bypass Issues, 
http://cwe.mitre.org/data/definitions/592.html, web site last accessed 
December 01, 2015.

b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8214, web 
site last accessed December 01, 2015.

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 December 01, 2015.

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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