A vulnerability in the ntp subsystem of Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to mobilize ntp associations.
The vulnerability is due to missing authorization checks on certain ntp packets. An attacker could exploit this vulnerability by ingressing malicious packets to the ntp daemon. An exploit could allow the attacker to control the time of the affected device.
Cisco has released software updates that address this vulnerability. Workarounds that address this vulnerability are not available.
This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160419-ios
Vulnerable ProductsThe following Cisco products are vulnerable:
- Cisco IOS Releases: Consult the Cisco bug ID release note for a full list of affected Cisco IOS Software trains
- Cisco IOS XE 3.2.0 to 3.18.0S
Products Confirmed Not VulnerableCisco IOS major release trains 12.0, 12.1, 12.2, 12.3, and 12.4 are not affected by this vulnerability. Consult the Cisco bug ID release note for a full list of affected Cisco IOS Software trains.
Workarounds are not available; however, mitigations can be implemented to help reduce the exposure.
- Use ntp authenticate to block all unauthenticated ntp associations, unless unauthenticated ntp is required.
- Use access control lists (ACLs) to control the network ranges that can ingress ntp packets.
When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to upgrade 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.
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.
This vulnerability was found during an internal security audit of the product and was introduced as part of a code change. Consult the Cisco bug ID release note for a full list of affected Cisco IOS Software trains.
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.
Version Description Section Status Date 1.2 Updated affected release information. Affected Products and Source Final 2016-September-27 1.1 Updated information. Affected Products Final 2016-June-23 1.0 Initial public release. — Final 2016-April-19
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