Cisco Security Advisory
Cisco IOS and IOS XE Software Internet Key Exchange Version 1 RSA-Encrypted Nonces Vulnerability

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:X/RL:X/RC:X
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A vulnerability in the implementation of RSA-encrypted nonces in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to obtain the encrypted nonces of an Internet Key Exchange Version 1 (IKEv1) session.
The vulnerability exists because the affected software responds incorrectly to decryption failures. An attacker could exploit this vulnerability sending crafted ciphertexts to a device configured with IKEv1 that uses RSA-encrypted nonces. A successful exploit could allow the attacker to obtain the encrypted nonces.
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-20180813-rsa-nonce
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Vulnerable Products
This vulnerability affects Cisco IOS Software and Cisco IOS XE Software that is configured with the authentication rsa-encr option. For information about affected software releases, consult the Cisco bug ID(s) at the top of this advisory.Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that the vulnerability does not affect Cisco IOS XR Software.
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There are no workarounds that address this vulnerability.
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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.
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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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Cisco would like to thank Dennis Felsch, Martin Grothe, and Jörg Schwenk from Ruhr-Universität Bochum, as well as Adam Czubak and Marcin Szymanek from University of Opole, for reporting this vulnerability.
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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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Version Description Section Status Date 1.0 Initial public release. - Final 2018-August-13
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