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AUSCERT External Security Bulletin Redistribution
ESB-2017.1460
Cisco Network Convergence System 5500 Series Routers Local
Denial of Service Vulnerability
12 June 2017
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Network Convergence System 5500 Series
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2017-6666
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170607-ncs
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Cisco Security Advisory
Cisco Network Convergence System 5500 Series Routers Local Denial of Service
Vulnerability
Medium
Advisory ID:
cisco-sa-20170607-ncs
First Published:
2017 June 7 16:00 GMT
Version 1.0:
Final
Workarounds:
No workarounds available
Cisco Bug IDs:
CSCvd16665
CVE-2017-6666
CWE-399
CVSS Score:
Base 6.0, Temporal 6.0
CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
CVE-2017-6666
CWE-399
Summary
A vulnerability in the forwarding component of Cisco IOS XR Software for
Cisco Network Convergence System (NCS) 5500 Series Routers could allow an
authenticated, local attacker to cause the router to stop forwarding data
traffic across Traffic Engineering (TE) tunnels, resulting in a denial of
service (DoS) condition.
The vulnerability occurs because adjacency information for a Traffic
Engineering (TE) tunnel's physical source interface is not propagated to
hardware after the adjacency is lost. This information needs to be
relearned. An attacker could exploit this vulnerability by logging in to
the router's CLI with administrator privileges and issuing the clear
arp-cache command.
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-20170607-ncs
Affected Products
Vulnerable Products
This vulnerability affects Cisco NCS 5500 Series Routers. For information
about affected software releases, consult the Cisco bug ID(s) at the top of
this advisory.
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this
vulnerability.
Workarounds
There are no workarounds that address this vulnerability.
Mitigations
To recover a device from the affected state, tear down and then
re-establish the TE tunnel using the shutdown command followed by the no
shutdown command in tunnel configuration mode.
Fixed Software
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
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
This vulnerability was found during internal testing.
Cisco Security Vulnerability Policy
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.
Subscribe to Cisco Security Notifications
Subscribe
URL
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170607-ncs
Revision History
Version Description Section Status Date
1.0 Initial public release. Final 2017-June-07
Legal Disclaimer
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND
OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT
OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES
THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the
distribution URL is an uncontrolled copy and may lack important information
or contain factual errors. The information in this document is intended for
end users of Cisco products.
Cisco Security Vulnerability Policy
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.
Subscribe to Cisco Security Notifications
Subscribe
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