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AUSCERT External Security Bulletin Redistribution
ESB-2019.1330.2
Multiple security vulnerabilities patched in Cisco
Expressway and Cisco TelePresence VCS
6 May 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Expressway Series
Cisco TelePresence Video Communication Server
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Cross-site Request Forgery -- Remote with User Interaction
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2019-1722 CVE-2019-1721 CVE-2019-1720
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-ex-vcs-xsrf
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-ces-tvcs-dos
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-es-tvcs-dos
Revision History: May 6 2019: Added mitigation for cisco-sa-20190417-es-tvcs-dos
April 18 2019: Initial Release
- --------------------------BEGIN INCLUDED TEXT--------------------
Cisco Expressway Series and Cisco TelePresence Video Communication Server
Cross-Site Request Forgery Vulnerability
Priority: Medium
Advisory ID: cisco-sa-20190417-ex-vcs-xsrf
First Published: 2019 April 17 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvn47520
CVE-2019-1722
CWE-352
CVSS Score:
6.5 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N/E:X/RL:X/RC:X
Summary
o A vulnerability in the FindMe feature of Cisco Expressway Series and Cisco
TelePresence Video Communication Server (VCS) could allow an
unauthenticated, remote attacker to conduct a cross-site request forgery
(CSRF) attack and perform arbitrary actions on an affected system.
The vulnerability is due to insufficient CSRF protections for the web-based
management interface of the affected system. An attacker could exploit this
vulnerability by persuading a user of the interface to follow a maliciously
crafted link. A successful exploit could allow the attacker to perform
arbitrary actions on an affected system with the privileges of the user.
The arbitrary actions include adding an attacker-controlled device and
redirecting calls intended for a specific user.
For more information about CSRF attacks and potential mitigations, see
Understanding Cross-Site Request Forgery Threat Vectors .
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-ex-vcs-xsrf
Affected Products
o Vulnerable Products
This vulnerability affects Cisco Expressway Series and Cisco TelePresence
Video Communication Server (VCS). For information about affected software
releases, consult the Cisco bug ID(s) at the top of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o For information about fixed software releases , consult the Cisco bug ID(s)
at the top of this advisory.
When considering software upgrades, customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories and Alerts page , to determine exposure and a
complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
Source
o This vulnerability was found during internal security testing.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-ex-vcs-xsrf
Revision History
o +---------+--------------------------+---------+--------+----------------+
| Version | Description | Section | Status | Date |
+---------+--------------------------+---------+--------+----------------+
| 1.0 | Initial public release. | - | Final | 2019-April-17 |
+---------+--------------------------+---------+--------+----------------+
- --------------------------------------------------------------------------------
Cisco Expressway Series and Cisco TelePresence Video Communication Server
Denial of Service Vulnerability
Priority: Medium
Advisory ID: cisco-sa-20190417-ces-tvcs-dos
First Published: 2019 April 17 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvn99036
CVE-2019-1720
CWE-20
CVSS Score:
6.8 AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Summary
o A vulnerability in the XML API of Cisco Expressway Series and Cisco
TelePresence Video Communication Server (VCS) could allow an authenticated,
remote attacker to cause the CPU to increase to 100% utilization, causing a
denial of service (DoS) condition on an affected system.
The vulnerability is due to improper handling of the XML input. An attacker
could exploit this vulnerability by sending a specifically crafted XML
payload. A successful exploit could allow the attacker to exhaust CPU
resources, resulting in a DoS condition until the system is manually
rebooted.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-ces-tvcs-dos
Affected Products
o Vulnerable Products
This vulnerability affects Cisco Expressway Series and Cisco TelePresence
Video Communication Server. For information about affected software
releases, consult the Cisco bug ID(s) at the top of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o For information about fixed software releases , consult the Cisco bug ID(s)
at the top of this advisory.
When considering software upgrades, customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories and Alerts page , to determine exposure and a
complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
Source
o This vulnerability was found during internal security testing.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-ces-tvcs-dos
Revision History
o +---------+--------------------------+---------+--------+----------------+
| Version | Description | Section | Status | Date |
+---------+--------------------------+---------+--------+----------------+
| 1.0 | Initial public release. | - | Final | 2019-April-17 |
+---------+--------------------------+---------+--------+----------------+
- --------------------------------------------------------------------------------
Cisco Expressway Series and Cisco TelePresence Video Communication Server
Denial of Service Vulnerability
Priority: High
Advisory ID: cisco-sa-20190417-es-tvcs-dos
First Published: 2019 April 17 16:00 GMT
Last Updated: 2019 May 3 19:50 GMT
Version 1.1: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvn99037
CVE-2019-1721
CWE-20
CVSS Score:
7.7 AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Summary
o A vulnerability in the phone book feature of Cisco Expressway Series and
Cisco TelePresence Video Communication Server (VCS) could allow an
authenticated, remote attacker to cause the CPU to increase to 100%
utilization, causing a denial of service (DoS) condition on an affected
system.
The vulnerability is due to improper handling of the XML input. An attacker
could exploit this vulnerability by sending a Session Initiation Protocol
(SIP) message with a crafted XML payload to an affected device. A
successful exploit could allow the attacker to exhaust CPU resources,
resulting in a DoS condition. Manual intervention may be required to
recover the device.
Cisco has released software updates that address this vulnerability. There
are no workarounds that address this vulnerability. Mitigation options that
address this vulnerability are available.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-es-tvcs-dos
Affected Products
o Vulnerable Products
This vulnerability affects Cisco Expressway Series and Cisco TelePresence
Video Communication Server releases prior to X12.5.1.
Administrators can log in to the web-based GUI of Cisco Expressway Series
or Cisco TelePresence VCS and view the current version in the lower-right
corner in the Version field. Alternatively, administrators can view the
Software version field by navigating to Status > System > Information.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability; however, there
are mitigation options.
Option 1
Disable SIP if not required: Disabling SIP will completely close the attack
vector for this vulnerability. However, it may not be suitable for all
customers because it is a required feature in many environments.
To disable SIP from the web admin UI, navigate to Configuration > Protocols
> SIP , and under the Configuration section, set SIP mode to Off and click
Save .
Option 2
Disable Provisioning services if not required: Disabling Provisioning
services will completely close the attack vector for this vulnerability.
However, it may not be suitable for all customers because it is a required
feature in many environments.
To disable Provisioning services from the web admin UI, the steps depend on
the software version in use:
For releases X8.11 and later, navigate to System > Administration
settings , and under the Services section, set Provisioning services to
Off and click Save .
For releases prior to X8.11, disable the Phone Book server by removing
all Provisioning (P) or Starter Pack (S) option keys.
Fixed Software
o Cisco has released free software updates that address the vulnerability
described in this advisory. Customers may only install and expect support
for software versions and feature sets for which they have purchased a
license. By installing, downloading, accessing, or otherwise using such
software upgrades, customers agree to follow the terms of the Cisco
software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html
Additionally, customers may only download software for which they have a
valid license, procured from Cisco directly, or through a Cisco authorized
reseller or partner. In most cases this will be a maintenance upgrade to
software that was previously purchased. Free security software updates do
not entitle customers to a new software license, additional software
feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories and Alerts page , to determine exposure and a
complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service
contract and customers who make purchases through third-party vendors but
are unsuccessful in obtaining fixed software through their point of sale
should obtain upgrades by contacting the Cisco TAC:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared
to provide the URL of this advisory as evidence of entitlement to a free
upgrade.
Fixed Releases
This vulnerability is fixed in Cisco Expressway Series and Cisco
TelePresence Video Communication Server Releases X12.5.1 and later.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
Source
o This vulnerability was found during internal security testing.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
Action Links for This Advisory
o Snort Rule 49858
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-es-tvcs-dos
Revision History
o +---------+------------------------+-------------+--------+---------------+
| Version | Description | Section | Status | Date |
+---------+------------------------+-------------+--------+---------------+
| 1.1 | Added mitigation steps | Workarounds | Final | 2019-May-03 |
| | for older releases. | | | |
+---------+------------------------+-------------+--------+---------------+
| 1.0 | Initial public | - | Final | 2019-April-17 |
| | release. | | | |
+---------+------------------------+-------------+--------+---------------+
- --------------------------END INCLUDED TEXT--------------------
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The University of Queensland
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