Cisco Security Advisory: Cisco IOS Software Multicast Network Time Protocol Denial of Service Vulnerability

[Cisco Systems Product Security Incident Response Team <psirt () cisco com>]

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Cisco IOS Software Multicast Network Time Protocol Denial of Service Vulnerability

Advisory ID: cisco-sa-20130925-ntp

Revision 1.0

For Public Release 2013 September 25 16:00  UTC (GMT)
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Summary
=======

A vulnerability in the implementation of the Network Time Protocol (NTP) feature in Cisco IOS Software could allow an 
unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) 
condition.

The vulnerability is due to the improper handling of multicast NTP packets that are sent to an affected device 
encapsulated in a Multicast Source Discovery Protocol (MSDP) Source-Active (SA) message from a configured MSDP peer. An 
attacker could exploit this vulnerability by sending multicast NTP packets to an affected device. Repeated exploitation 
could result in a sustained DoS condition.

Cisco has released free software updates that address this vulnerability. A workaround is available to mitigate this 
vulnerability.

This advisory is available at the following link: 
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ntp

Note: The September 25, 2013, Cisco IOS Software Security Advisory bundled publication includes eight Cisco Security 
Advisories. All advisories address vulnerabilities in Cisco IOS Software. Each Cisco IOS Software Security Advisory 
lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as 
well as the Cisco IOS Software releases that correct all Cisco IOS Software vulnerabilities in the September 2013 
bundled publication.

Individual publication links are in "Cisco Event Response: Semiannual Cisco IOS Software Security Advisory Bundled 
Publication" at the following link: http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep13.html

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