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             AUSCERT External Security Bulletin Redistribution

           SubSTATION Server Telegyr 8979 Master Vulnerabilities
                               4 August 2014


        AusCERT Security Bulletin Summary

Product:           SubSTATION Server 2 Telegyr 8979 Master Protocol
Publisher:         ICS-CERT
Operating System:  Windows
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2014-2357  

Original Bulletin: 

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Advisory (ICSA-14-196-01)

SubSTATION Server Telegyr 8979 Master Vulnerabilities

Original release date: July 31, 2014

Legal Notice

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This advisory was originally posted to the US-CERT secure Portal library
on July 15, 2014, and is being released to the NCCIC/ICS-CERT web site.

Adam Crain of Automatak and Chris Sistrunk of Mandiant have identified
a Buffer Overflow Vulnerability in the SUBNET Solutions Inc (SUBNET),
SubSTATION Server 2, Telegyr 8979 Master application. SUBNET has produced
a hot fix that mitigates this and a related vulnerability the vendor found
independently. The researchers have tested the new hot fix and validate
that it resolves these vulnerabilities.

These vulnerabilities could be exploited remotely.

The following SUBNET product is affected:

    SubSTATION Server 2 Telegyr 8979 Master Protocol – All Versions.


By sending specially crafted invalid RTU messages to the Telegyr 8979
master, a buffer overflow can occur, resulting in a denial of service (DoS).

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.


SUBNET is based in Calgary, Alberta, Canada.

The affected product, SubSTATION Server, is a vendor agnostic multifunction
software application used in intelligent substation automation and IT
networking. SubSTATION Server performs data concentration, protocol
translation, automation logic, event file collection, and enterprise
connectivity. This allows replacement of separate legacy devices, such
as RTU data concentrators, relay communications processors used in the
operation of electrical substations. According to SUBNET, SubSTATION
Server is deployed in the Energy sector including oil and gas and electric
utilities. SUBNET estimates that these products are used primarily in the
United States and Canada.




The researchers found that by sending a specially crafted packet simulating
an RTU to Master message exceeding allowable data length, an attacker can
cause the Telegyr 8979 Master to crash. SUBNET has also discovered that
after sending a specially crafted message containing a valid data length,
any subsequent message sent immediately to the Telegyr 8979 will also
crash the service. SUBNET had also determined the root issue was in the
GPT software library.

CVE-2014-2357[b] has been assigned to this vulnerability. A CVSS
v2 base score of 8.3 has been assigned; the CVSS vector string is



These vulnerabilities could be exploited remotely.


No known public exploits specifically target these vulnerabilities.


Crafting a working exploit for these vulnerabilities would be difficult. An
attacker with a moderate to high skill level would be able to exploit
these vulnerabilities.


SUBNET has produced hot fix “SSNET v2.12 HF18808” to resolve this issue.

This hot fix can be obtained by secure FTP provided by the SUBNET support
department. Please contact SUBNET Customer Support at: (403) 270-8885,
or by email at: support@SUBNET.com and reference SUBNET Release Bulletin
“SubSTATION Server 2.12 HF18808 Release, 21  May 2014” for a copy of
this release bulletin and download/installation information (This bulletin
is being sent to registered users only).

Vendor Recommendation:

    The exploit results in an unrecoverable exception, but all software
    components are registered as Services under Windows and can be
    configured to automatically restart after any stoppage. Users can
    configure the service to automatically restart, which limits the DoS
    to a momentary disruption.
    Backward compatible releases will be available by request for customers
    using older versions of SubSTATION Server.

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 ICS‑CERT 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-20: Improper Input Validation,
    http://cwe.mitre.org/data/definitions/20.html, web site last accessed
    July 15, 2014.
    b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-2357,
    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,
    web site last accessed July 15, 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:

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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