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             AUSCERT External Security Bulletin Redistribution

                               ESB-2016.2799
 Siemens SIMATIC CP 1543-1 Vulnerabilities and Siemens SIMATIC CP 343-1/CP
       443-1 Modules and SIMATIC S7-300/S7-400 CPUs Vulnerabilities
                             23 November 2016

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

Product:           SIMATIC CP 1543-1
                   SIMATIC CP 343-1
                   SIMATIC CP 443-1
                   SIMATIC S7-300
                   SIMATIC S7-400
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Execute Arbitrary Code/Commands -- Remote with User Interaction
                   Access Privileged Data          -- Remote/Unauthenticated      
                   Increased Privileges            -- Existing Account            
                   Denial of Service               -- Existing Account            
Resolution:        Patch/Upgrade
CVE Names:         CVE-2016-8673 CVE-2016-8672 CVE-2016-8562
                   CVE-2016-8561  

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSA-16-327-01
   https://ics-cert.us-cert.gov/advisories/ICSA-16-327-02

Comment: This bulletin contains two (2) ICS-CERT security advisories.

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

Advisory (ICSA-16-327-01)

Siemens SIMATIC CP 1543-1 Vulnerabilities

Original release date: November 22, 2016

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 released an advisory to inform its users how to mitigate
vulnerabilities that affect SIMATIC CP 1543-1. These vulnerabilities were
coordinated directly with Siemens by SOGETI and Agence nationale de la
sécurité des systèmes d'information (ANSSI). Siemens has produced a
firmware to mitigate these vulnerabilities.

These vulnerabilities could be exploited remotely.

AFFECTED PRODUCTS

Siemens reports that the vulnerabilities affect the following versions of
SIMATIC CP 1543-1:

    SIMATIC CP 1543-1: All versions prior to V2.0.28

IMPACT

An attacker who exploits these vulnerabilities may be able to elevate
privileges on the affected devices or cause a denial-of-service condition.

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

The affected product, SIMATIC CP 1543-1 communication processor, connects the
S7-1500 controller to Ethernet networks. It provides integrated security
functions, such as firewall and virtual private networks (VPNs), and
supports other protocols with data encryption such as FTP. The communication
processor protects S7-1500 stations against unauthorized access, as well
as integrity and confidentiality of transmitted data. According to Siemens,
this product is deployed across several sectors including Chemical, Energy,
Food and Agriculture, and Water and Wastewater Systems. Siemens estimates
that these products are used worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

IMPROPER INPUT VALIDATION[a]

Users with elevated privileges to TIA-Portal and project data on the
engineering station could possibly get privileged access on affected devices.

CVE-2016-8561[b] has been assigned to this vulnerability. A CVSS
v3 base score of 6.6 has been calculated; the CVSS vector string is
(AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H).[c]

IMPROPER PRIVILEGE MANAGEMENT[d]

Under special conditions, it may be possible to write SNMP variables on
Port 161/UDP that should be read-only and should only be configured with
TIA-Portal. A write to these variables could reduce the availability or
cause a denial of service.

CVE-2016-8562[e] has been assigned to this vulnerability. A CVSS
v3 base score of 5.3 has been calculated; the CVSS vector string is
(AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H).[f]

VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target these vulnerabilities.

DIFFICULTY

Crafting a working exploit for these vulnerabilities would be difficult.

MITIGATION

Siemens provides firmware update V2.0.28 for SIMATIC CP 1543-1 devices,
which fixes the vulnerabilities, and recommends users update to the new
version. This update can be found on the Siemens web site at the following
location:

https://support.industry.siemens.com/cs/ww/en/view/109743137 (link is
external)

Siemens strongly recommends users protect network access to the management
interface of perimeter devices with appropriate mechanisms. Siemens also
advises that users configure the operational environment according to
Siemens' Operational Guidelines for Industrial Security:

https://www.siemens.com/cert/operational-guidelines-industrial-security
(link is external)

For more information on this vulnerability and more detailed mitigation
instructions, please see Siemens Security Advisory SSA-672373 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. 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 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,
    https://cwe.mitre.org/data/definitions/20.html, web site last accessed
    November 22, 2016.
    b.
    NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8561,
    web site last accessed November 22, 2016.
    c.
    CVSS Calculator,
    https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S...,
    web site last accessed November 22, 2016.
    d.
    CWE-269: Improper Privilege Management,
    https://cwe.mitre.org/data/definitions/269.html, web site last accessed
    November 22, 2016.
    e.
    NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8562,
    web site last accessed November 22, 2016.
    f.
    CVSS Calculator,
    https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S...,
    web site last accessed November 22, 2016.


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.

- ---

Advisory (ICSA-16-327-02)

Siemens SIMATIC CP 343-1/CP 443-1 Modules and SIMATIC S7-300/S7-400 CPUs
Vulnerabilities

Original release date: November 22, 2016

Print Document

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 released an advisory regarding vulnerabilities affecting SIMATIC
CP 343-1 Advanced/CP-443-1 Advanced devices and SIMATIC S7-300/S7-400
CPUs. Inverse Path auditors and the Airbus ICT Industrial Security team
reported these vulnerabilities directly to Siemens. Siemens has made new
firmware versions available for several products and a temporary fix for
the remaining affected products to mitigate these vulnerabilities.

These vulnerabilities could be exploited remotely.

AFFECTED PRODUCTS

Siemens reports that the vulnerabilities affect the following SIMATIC
products:

    SIMATIC CP 343-1 Advanced: All versions prior to V3.0.53,
    SIMATIC CP 443-1 Advanced: All versions,
    SIMATIC S7-300 CPU family: All firmware versions, and
    SIMATIC S7-400 CPU family: All firmware versions.

IMPACT

Under certain conditions, an attacker could use these vulnerabilities to
perform operations as an authenticated user.

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

Communication Processor (CP) modules SIMATIC CP 343-1 Advanced and CP 443-1
Advanced are designed to enable SIMATIC S7-300/S7-400 CPUs to communicate
via Ethernet.

According to Siemens, several critical infrastructure (CI) sectors deploy
these products, including Chemical, Critical Manufacturing, and Food and
Agriculture. Siemens estimates that users of these products are located
worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

INSUFFICIENT VERIFICATION OF DATA AUTHENTICITY[a]

The integrated web server at Port 80/TCP or Port 443/TCP of the affected
devices could allow remote attackers to perform actions with the permissions
of an authenticated user, provided the targeted user has an active session
and is induced to trigger the malicious request.

CVE-2016-8673[b] has been assigned to this vulnerability. A CVSS
v3 base score of 6.3 has been calculated; the CVSS vector string is
(AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L).[c]

SENSITIVE COOKIE IN HTTPS SESSION WITHOUT 'SECURE' ATTRIBUTE[d]

The integrated web server delivers cookies without the "secure" flag. Modern
browsers interpreting the flag would mitigate potential data leakage in
case of clear text transmission.

CVE-2016-8672[e] has been assigned to this vulnerability. A CVSS
v3 base score of 4.0 has been calculated; the CVSS vector string is
(AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N).[f]

VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target these vulnerabilities.

DIFFICULTY

An attacker with a low skill may be able to exploit these vulnerabilities.

MITIGATION

Siemens provides firmware versions that fix the vulnerabilities and
recommends that users update to the fixed versions:

    SIMATIC CP 343-1 Advanced: Update to V3.0.53:

https://support.industry.siemens.com/cs/ww/en/view/109742236 (link is
external)

For SIMATIC CP 443-1 Advanced devices, Siemens recommends the following
mitigations:

    Restrict web server access to the internal network,
    Use VPN for protecting network communication on the external network
    interface, and
    Follow operational guidelines.

For SIMATIC S7-300/S7-400 CPUs, Siemens recommends the following mitigations:

    Apply cell protection concept,
    Use VPN for protecting network communication between cells, and
    Apply Defense-in-Depth.

Siemens strongly recommends users protect network access to SIMATIC
S7-300/S7-400 CPUs and to the web interface of SIMATIC CP 343-1 Advanced
and CP 443-1 Advanced devices with appropriate mechanisms. Siemens also
advises that users configure the protected operational environment according
to Siemens' Operational Guidelines for Industrial Security:

https://www.siemens.com/cert/operational-guidelines-industrial-security
(link is external)

For more information on this vulnerability and more detailed mitigation
instructions, please see Siemens Security Advisory SSA-603476 at the
following location:

http://www.siemens.com/cert/advisories (link is external)

Siemens will update SSA-603476 and ICS-CERT will update this advisory when
new information becomes available.

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. 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 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-345: Insufficient Verification of Data Authenticity,
    https://cwe.mitre.org/data/definitions/345.html, web site last accessed
    November 22, 2016.
    b.
    NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8673,
    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,
    https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S...,
    web site last accessed November 22, 2016.
    d.
    CWE-614: Sensitive Cookie in HTTPS Session Without 'Secure' Attribute,
    https://cwe.mitre.org/data/definitions/614.html, web site last accessed
    November 22, 2016.
    e.
    NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8672,
    NIST uses this advisory to create the CVE web site report. This web
    site will be active sometime after publication of this advisory.
    f.
    CVSS Calculator,
    https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S...,
    web site last accessed November 22, 2016.


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.

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

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