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AUSCERT External Security Bulletin Redistribution
ESB-2019.1521
Cisco IP Phone 7800 Series and 8800 Series Session Initiation Protocol XML
2 May 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco IP Phone 7800 Series and 8800 Series
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2019-1635
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-phone-sip-xml-dos
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Cisco IP Phone 7800 Series and 8800 Series Session Initiation Protocol XML
Denial of Service Vulnerability
Priority: High
Advisory ID: cisco-sa-20190501-phone-sip-xml-dos
First Published: 2019 May 1 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvm39405CSCvo19825CSCvo21348CSCvo23532
CVE-2019-1635
CWE-399
CVSS Score:
7.5 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:X/RL:X/RC:X
Summary
o A vulnerability in the call-handling functionality of Session Initiation
Protocol (SIP) Software for Cisco IP Phone 7800 Series and 8800 Series
could allow an unauthenticated, remote attacker to cause an affected phone
to reload unexpectedly, resulting in a temporary denial of service (DoS)
condition.
The vulnerability is due to incomplete error handling when XML data within
a SIP packet is parsed. An attacker could exploit this vulnerability by
sending a SIP packet that contains a malicious XML payload to an affected
phone. A successful exploit could allow the attacker to cause the affected
phone to reload unexpectedly, resulting in a temporary DoS condition.
Cisco has released software updates that address this vulnerability. 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-20190501-phone-sip-xml-dos
Affected Products
o Vulnerable Products
This vulnerability affects the following Cisco products if they are running
a SIP Software release prior to the first fixed release:
IP Conference Phone 7832
IP Conference Phone 8832
IP Phone 7811
IP Phone 7821
IP Phone 7841
IP Phone 7861
IP Phone 8811
IP Phone 8841
IP Phone 8845
IP Phone 8851
IP Phone 8861
IP Phone 8865
Unified IP 8831 Conference Phone ^ 1
Unified IP 8831 Conference Phone for Third-Party Call Control ^ 2
Wireless IP Phone 8821
Wireless IP Phone 8821-EX
^ 1 The fix for Cisco Unified IP 8831 Conference Phone is targeted for late
2019.
^ 2 No fix is available for Cisco Unified IP 8831 Conference Phone for
Third-Party Call Control.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Cisco has confirmed that IP Phones running Multiplatform Firmware are not
affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
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
Cisco fixed this vulnerability in the following SIP Software releases:
11.0(5) and later for Cisco Wireless IP Phone 8821 and 8821-EX
12.5(1) and later for the rest of the Cisco IP Phone 7800 Series and
8800 Series ^ 1,2
1. The fix for Cisco Unified IP 8831 Conference Phone is targeted for late
2019.
2. No fix is available for Cisco Unified IP 8831 Conference Phone for
Third-Party Call Control.
Customers can download the SIP Software from the Software Center on
Cisco.com by doing the following:
1. Click Browse all .
2. Choose Collaboration Endpoints > IP Phones > IP Phone 7800 Series or IP
Phone 8800 Series > [Model] > Session Initiation Protocol (SIP)
Software .
3. Access releases by using the left pane of the page.
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 the resolution of a Cisco TAC support
case.
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-20190501-phone-sip-xml-dos
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2019-May-01 |
+----------+---------------------------+----------+--------+--------------+
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