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             AUSCERT External Security Bulletin Redistribution

             Siemens RUGGEDCOM ROS IP Forwarding Vulnerability
                             3 September 2015


        AusCERT Security Bulletin Summary

Product:           Siemens RUGGEDCOM ROS
Publisher:         US-CERT
Operating System:  Network Appliance
Impact/Access:     Unauthorised Access -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2015-6675  

Original Bulletin: 

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Advisory (ICSA-15-244-01)

Siemens RUGGEDCOM ROS IP Forwarding Vulnerability

Original release date: September 01, 2015

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Stephen Craven of the Tennessee Valley Authority (TVA) has identified an IP 
forwarding vulnerability in older versions of Siemens RUGGEDCOM ROS. Siemens 
recommends updating to the latest version to mitigate this vulnerability.

This vulnerability could be exploited remotely.


Siemens reports that the vulnerability affects the following versions of 

    ROS: All versions between 3.8.0 and 4.2.0

ROS on the following products is not affected:

    RMC products,

    RP110, and



An attacker in one VLAN could possibly circumvent VLAN isolation and 
communicate with devices in another VLAN if IP addresses are configured on 
both VLANs.

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.


Siemens is an international company headquartered in Munich, Germany.

The affected products, Siemens RUGGEDCOM ROS-based devices, are used to 
connect devices that operate in harsh environments such as electric utility 
substations and traffic control cabinets. According to Siemens, RUGGEDCOM 
ROS-based devices are deployed across several sectors including Energy, 
Healthcare and Public Health, and Transportation Systems. Siemens estimates 
that these products are used worldwide.




The ROS operating system for layer 2 switches include IP forwarding 
capabilities that cannot be deactivated by users. This may allow an attacker 
in one VLAN to possibly circumvent VLAN isolation and communicate with devices
in another VLAN if IP addresses are configured on both VLANs.

CVE-2015-6675 [b] has been assigned to this vulnerability. A CVSS v2 base score 
of 4.3 has been assigned; the CVSS vector string is 
(AV:A/AC:M/Au:N/C:P/I:P/A:N). [c]



This vulnerability could be exploited remotely.


No known public exploits specifically target this vulnerability.


An attacker with a medium skill would be able to exploit this vulnerability.


Firmware versions since ROS 4.2.0 provide an option to disable IP forwarding.
Siemens recommends that users update to the latest firmware version. The 
firmware updates for the affected products can be obtained for free from the 
following contact points:

    Submit a support request online


    Call a local hotline center:


If users do not want IP forwarding between VLANs in their configuration, then
they need to disable IP forwarding after updating to the new firmware 
according to the instructions in the user guide. The following link leads to 
the ROS user guide:


Until the firmware can be updated to the latest version, users can remove IP 
addresses from the VLAN if they are not required.

For more information on this vulnerability and detailed instructions, please 
see Siemens Security Advisory SSA-720081 at the following location:


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 

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-441: Unintended Proxy or Intermediary ('Confused Deputy'), 
http://cwe.mitre.org/data/definitions/441.html, web site last accessed 
September 1, 2015.

b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-6675, 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:A/AC:M/Au:N/C:P/I:P/A:N, web
site last accessed September 1, 2015.

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: 

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 

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