Cisco Security Advisory
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AV:N/AC:M/Au:N/C:P/I:P/A:N/E:F/RL:OF/RC:C
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A vulnerability in the implementation of X.509 Version 3 for SSH authentication functionality in Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to bypass authentication on an affected system.
The vulnerability is due to improper validation of X.509 signatures during the SSH authentication phase. An attacker could exploit this vulnerability by presenting an invalid X.509 signature to an affected system. A successful exploit could allow the attacker to impersonate an existing valid user over an SSH connection.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161207-ios-xe-x509
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Vulnerable Products
This vulnerability affects Cisco IOS and IOS XE Software. For information about which software releases are vulnerable, consult the Cisco bug ID at the top of this advisory.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 address this vulnerability. As a mitigation, administrators may disable the X.509 authentication feature on an affected device until the device is upgraded to a fixed release of the software.
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For information about fixed software releases, consult the Cisco bug ID 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.
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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 2016-December-07
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