Cisco Security Advisory
Cisco IOS and IOS XE Software IKEv1 State Machine Denial of Service Vulnerability
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AV:N/AC:L/Au:N/C:N/I:N/A:P/E:F/RL:OF/RC:C
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A vulnerability in the Internet Key Exchange (IKEv1) state machine of Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to tear down valid IPsec connections, resulting in a partial denial of service (DoS) condition.
The vulnerability is due to insufficient condition checks in the IKEv1 state machine. An attacker could exploit this vulnerability by sending a spoofed, specific IKEv1 packet to an endpoint of an IPsec tunnel. A successful exploit could allow the attacker to tear down IPsec tunnels that terminate on the endpoint, causing a partial DoS condition.
Cisco has released software updates that address this vulnerability. There are no workarounds that mitigate this vulnerability.
This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151218-ios
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Vulnerable Products
Cisco IOS and Cisco IOS XE Software Releases prior to 15.5(2)S2 (3.15.2S), 15.5(2)T2, 15.5(3)M1, 15.5(3)S1 (3.16.1S), 15.6(1)S (3.17.1S), and 15.6(1)T are vulnerable.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this vulnerability.
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There are no workarounds that mitigate this vulnerability.
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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.
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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.
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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.
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Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2015-December-18
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