ESB-2017.2307 - [Appliance] Philips IntelliView MX40 Patient Worn Monitor: Denial of service - Remote/unauthenticated 2017-09-13

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2017.2307
   Philips' IntelliView MX40 Patient Worn Monitor (WLAN) Vulnerabilities
                             13 September 2017

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

Product:           Philips IntelliView MX40 Patient Worn Monitor
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-9658 CVE-2017-9657 

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSMA-17-255-01

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Advisory (ICSMA-17-255-01)

Philips' IntelliView MX40 Patient Worn Monitor (WLAN) Vulnerabilities

Original release date: September 12, 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/.

OVERVIEW

Philips has identified two vulnerabilities in Philips' IntelliView MX40 
Patient Worn Monitor for use with wireless local area networks (WLANs). 
Philips has produced a software update that fixes one of the identified 
vulnerabilities and provides mitigations for the other vulnerability. Philips
plans to release an additional software update in 2017 to address the 
remaining vulnerability.

AFFECTED PRODUCTS

The following versions of the IntelliVue MX40 Patient Worn Monitor are 
affected:

IntelliVue MX40 Patient Worn Monitor (WLAN only), all versions prior to 
Version B.06.18

Vulnerabilities only affect MX40 WLAN monitors operating on a user-provided 
802.11 wireless LAN. MX40 monitors with 1.4 GHz and 2.4 GHz Smart-Hopping 
radios are not affected.

IMPACT

Successful exploitation of these vulnerabilities may allow an attacker to 
issue 802.11 Wi-Fi management commands that can impact reporting availability
of MX40 device local monitoring to a central monitoring station. If a patient
experiences an alarm event and clinical staff expects the MX40 to provide 
local alarming (local audio-on, local screen-on) when it is not available from
the local device, a delay of treatment can occur.

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 and specific 
clinical usage.

BACKGROUND

Philips is a global company that maintains offices in several countries around
the world, including countries in Africa, Asia, Europe, Latin America, the 
Middle East, and North America.

The MX40 patient worn monitor is intended to be used primarily as a 
traditional telemetry medical device as part of a monitoring and alerting 
system. As such, the MX40 (WLAN) connects to a central monitoring station by 
way of a wireless network to operate in compliance with required behaviors 
that ensure the central station maintains device status, and the local MX40 
device continues to operate in local monitoring and alarming mode in the event
of a Wi-Fi network access anomaly. When the MX40 is connected to a central 
monitoring station, the central monitor provides the primary patient 
monitoring and alarming function, and the local MX40 device operates in 
telemetry mode (local audio off, local screen off). The MX40 is designed to:

Operate in telemetry mode (local audio-off, local screen-off) to communicate 
status and alerts to hospital staff at the central monitoring station.

Switch from telemetry mode into local monitoring mode (local audio-on, local 
screen-on) if certain Wi-Fi network management conditions or commands are 
encountered to de-authenticate MX40 from the Wi-Fi until either Wi-Fi network
conditions resume to enable MX40 to reconnect and re-associate to central 
monitoring, or until hospital staff intervene to reset and reconnect the 
device.

"Blacklist" the Wi-Fi access point in response to certain conditions as a 
security defense from further use until the device is reset by hospital staff.

According to Philips, the MX40 is deployed across the Healthcare and Public 
Health sector. Philips estimates these products are used primarily in the 
United States with users also in Canada, Europe, Australia, Africa, Latin 
America, Asia, and the Middle East.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

IMPROPER CLEANUP ON THROWN EXCEPTION[a]

Under specific 802.11 network conditions, a partial re-association of the MX40
WLAN monitor to the central monitoring station is possible. In this state, the
central monitoring station can indicate the MX40 is not connected or 
associated to the central monitor, and thus should be operating in local 
monitoring mode (local audio-on, screen-on), but the MX40 WLAN itself can 
instead still be operating in telemetry mode (local audio-off, screen-off). If
a patient experiences an alarm event and clinical staff expects the MX40 to 
provide local alarming when it is not available from the local device, a delay
of treatment can occur.

CVE-2017-9657[b] has been assigned to this vulnerability. A CVSS v3 base score 
of 6.5 has been assigned; the CVSS vector string is 
(AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).[c]

IMPROPER HANDLING OF EXCEPTIONAL CONDITIONS[d]

Certain 802.11 network management messages have been determined to invoke 
wireless access point blacklisting security defenses when not required, which
can necessitate intervention by hospital staff to reset the device and 
reestablish a network connection to the Wi-Fi access point. During this state,
the MX40 can either connect to an alternative access point within signal range
for association to a central monitoring station, or it can remain in local 
monitoring mode until the device is reset by hospital staff.

CVE-2017-9658[e] has been assigned to this vulnerability. A CVSS v3 base score 
of 6.5 has been assigned; the CVSS vector string is 
(AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).[f]

VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited via an adjacent network.

EXISTENCE OF EXPLOIT

No known public exploits specifically target these vulnerabilities.

DIFFICULTY

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

MITIGATION

Philips has released software update, Version B.06.18, to fix the improper 
cleanup on thrown exception vulnerability, and implement mitigations to reduce
the risk associated with the improper handling of exceptional conditions 
vulnerability. The software update implements messaging and alarming on the 
MX40 and at the central monitoring station, when the MX40 disconnects from the
access point.

For additional information about the vulnerabilities or the proposed 
mitigations, please contact Philips. Philips contact information is available
at the following location:

http://www.usa.philips.com/healthcare/solutions/customer-service-solutions

Philips is planning to release an additional MX40 software update in 2017 to 
address the improper handling of exceptional conditions vulnerability.

Please see the Philips product security web site for latest information for 
this and other Philips products:

https://www.usa.philips.com/healthcare/about/customer-support/product-security

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 medical devices and/or systems, and ensure 
that they are not accessible from the Internet.

Locate all medical devices 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 security recommended practices on the 
ICS-CERT web page at 
http://ics-cert.us-cert.gov/content/recommended-practices. 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 
(http://ics-cert.us-cert.gov/).

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-460: Improper Cleanup on Thrown Exception, 
http://cwe.mitre.org/data/definitions/460.html, web site last accessed 
September 12, 2017.

b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-9657, 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:A/AC:L/PR:N/UI:N/S..., 
web site last accessed September 12, 2017.

d. CWE-755: Improper Handling of Exceptional Conditions, 
http://cwe.mitre.org/data/definitions/755.html, web site last accessed 
September 12, 2017.

e. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-9658, 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:A/AC:L/PR:N/UI:N/S..., 
web site last accessed September 12, 2017.

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: 
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.

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