ESB-2017.3149 - [Appliance] ICS-CERT: Cross-site scripting - Remote with user interaction 2017-12-08

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2017.3149
        Advisory (ICSA-17-341-03) PHOENIX CONTACT FL COMSERVER, FL
                       COM SERVER, and PSI-MODEM/ETH
                              8 December 2017

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

Product:           FL COMSERVER
                   FL COM SERVER
                   PSI-MODEM/ETH
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Cross-site Scripting -- Remote with User Interaction
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-16723  

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSA-17-341-03

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Advisory (ICSA-17-341-03)

PHOENIX CONTACT FL COMSERVER, FL COM SERVER, and PSI-MODEM/ETH

Original release date: December 07, 2017

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/.

CVSS v3 8.2

ATTENTION: Remotely exploitable/low skill level to exploit.

Vendor: PHOENIX CONTACT

Equipment: FL COMSERVER, FL COM SERVER, and PSI-MODEM/ETH

Vulnerability: Cross-site Scripting

AFFECTED PRODUCTS

The following models running firmware versions prior to 1.99, 2.20, or 2.40 of
FL COMSERVER, FL COM SERVER, and PSI-MODEM/ETH, industrial networking 
equipment, are affected:

FL COMSERVER BASIC 232/422/485,

FL COMSERVER UNI 232/422/485,

FL COMSERVER BAS 232/422/485-T,

FL COMSERVER UNI 232/422/485-T,

FL COM SERVER RS232,

FL COM SERVER RS485, and

PSI-MODEM/ETH.

IMPACT

Successful exploitation of this vulnerability may allow a remote attacker to 
change configuration variables on the device.

MITIGATION

PHOENIX CONTACT has released new firmware versions for the affected devices. 
The latest download links can be found at:

https://cert.vde.com/de-de/advisories/vde-2017-004 (link is external)

NCCIC/ICS-CERT recommends that users take defensive measures to minimize the 
risk of exploitation of this vulnerability. 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 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.

No known public exploits specifically target this vulnerability.

VULNERABILITY OVERVIEW

IMPROPER NEUTRALIZATION OF INPUT DURING WEB PAGE GENERATION ('CROSS-SITE 
SCRIPTING') CWE-79

The cross-site scripting vulnerability has been identified, which may allow 
remote code execution.

CVE-2017-16723 has been assigned to this vulnerability. A CVSS v3 base score 
of 8.2 has been assigned; the CVSS vector string is 
(AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:H).

RESEARCHER

Maxim Rupp reported the vulnerability to ICS-CERT. CERT@VDE (link sends 
e-mail) coordinated the disclosure with Mr. Rupp and ICS-CERT.

BACKGROUND

Critical Infrastructure Sectors: Communications, Critical Manufacturing, 
Information Technology

Countries/Areas Deployed: Worldwide

Company Headquarters Location: Germany

Contact Information

For any questions related to this report, please contact the NCCIC at:

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov (link sends e-mail)

Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information: 
http://ics-cert.us-cert.gov

or incident reporting: https://ics-cert.us-cert.gov/Report-Incident?

The NCCIC 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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The University of Queensland
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