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             AUSCERT External Security Bulletin Redistribution

                               ESB-2019.0442
            Advisory (ICSA-19-043-06) Siemens CP1604 and CP1616
                             13 February 2019

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

Product:           Siemens CP1604 and CP1616
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service          -- Remote/Unauthenticated      
                   Cross-site Request Forgery -- Remote with User Interaction
                   Cross-site Scripting       -- Remote with User Interaction
                   Access Confidential Data   -- Remote/Unauthenticated      
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-13810 CVE-2018-13809 CVE-2018-13808

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSA-19-043-06

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Advisory (ICSA-19-043-06)

Siemens CP1604 and CP1616

Original release date: February 12, 2019

Legal Notice

All information products included in http://ics-cert.us-cert.gov are
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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/ .

1. EXECUTIVE SUMMARY

  o CVSS v3 9.1
  o ATTENTION : Exploitable remotely/low skill level to exploit
  o Vendor : Siemens
  o Equipment : CP1604 and CP1616
  o Vulnerabilities : Cleartext Transmission of Sensitive Information,
    Cross-site Scripting, Cross-site Request Forgery

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could result in a
denial-of-service condition and information exposure. An attacker could inject
arbitrary JavaScript in a specially crafted URL request to execute on
unsuspecting user's systems, allowing an attacker to trigger actions via the
web interface that a legitimate user is allowed to perform.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports the following CP products are affected:

  o CP 1604 and 1616: All versions prior to v2.8

3.2 VULNERABILITY OVERVIEW

3.2.1 CLEARTEXT TRANSMISSION OF SENSITIVE INFORMATION CWE-319
An attacker with network access to Port 23/TCP could extract internal
communication data or cause a denial-of-service condition.

CVE-2018-13808 has been assigned to this vulnerability. A CVSS v3 base score of
9.1 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:H/I:N/A:H ).

3.2.2 IMPROPER NEUTRALIZATION OF INPUT DURING WEB PAGE GENERATION ('CROSS-SITE
SCRIPTING') CWE-79
The integrated web server of the affected CP devices could allow cross-site
scripting (XSS) attacks if unsuspecting users are tricked into following a
malicious link.

CVE-2018-13809 has been assigned to this vulnerability. A CVSS v3 base score of
6.1 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:C/
C:L/I:L/A:N ).

3.2.3 CROSS-SITE REQUEST FORGERY CWE-352
The integrated configuration web server of the affected CP devices could allow
a cross-site request forgery (CSRF) attack if an unsuspecting user is tricked
into accessing a malicious link.

CVE-2018-13810 has been assigned to this vulnerability. A CVSS v3 base score of
4.3 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:U/
C:N/I:L/A:N )

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS : Chemical, Critical Manufacturing, Energy,
    Food and Agriculture,
    Water and Wastewater Systems
  o COUNTRIES/AREAS DEPLOYED : Worldwide
  o COMPANY HEADQUARTERS LOCATION : Germany

3.4 RESEARCHER

Siemens reported these vulnerabilities to NCCIC.

4. MITIGATIONS

Siemens recommends users update to version 2.8, which can be located here:

https://support.industry.siemens.com/cs/ww/en/view/109762689

Siemens has identified the following specific workarounds and mitigations users
can apply to reduce the risk:

  o Disable the integrated web server. The web server is disabled in the
    default settings and its use is optional. Use in a productive environment
    is discouraged.
  o Restrict access to the device to the internal or VPN network. Further
    restrict access to the web interface (80/TCP) and to the telnet port (23/
    TCP) to trusted IP addresses if possible.
  o Do not click on links from unknown sources.

As a general security measure, Siemens strongly recommends protecting network
access to devices with appropriate mechanisms. In order to operate the devices
in a protected IT environment, Siemens recommends configuring the environment
according to Siemens' operational guidelines for industrial security ( https://
www.siemens.com/cert/operational-guidelines-industrial-security ), and
following the recommendations in the product manuals.

Additional information on industrial security by Siemens can be found at:

https://www.siemens.com/industrialsecurity

For more information on these vulnerabilities and associated software updates,
please see Siemens security advisory SSA-559174 on their website:

https://www.siemens.com/cert/advisories

NCCIC recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:

  o Minimize network exposure for all control system devices and/or systems,
    and ensure that they are not accessible from the Internet .
  o Locate control system networks and remote devices behind firewalls, and
    isolate them from the business network.
  o 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.

NCCIC reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.

NCCIC 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
on the ICS-CERT website in the Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
Strategies .

Organizations observing any suspected malicious activity should follow their
established internal procedures and report their findings to NCCIC for tracking
and correlation against other incidents.

No known public exploits specifically target these vulnerabilities.

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