Cisco Security Advisory
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AV:N/AC:L/Au:N/C:P/I:N/A:N/E:F/RL:W/RC:C
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A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) feature of Cisco IOS could allow traffic to bypass the configured encryption policy.
The vulnerability is due to the default, implicit policies set in place to permit Group Domain of Interpretation (GDOI) traffic to flow unencrypted to allow the GET VPN group members (GMs) to communicate with the GET VPN key servers (KSs). Only transit or to the device traffic using UDP as the transport protocol and port 848 as either the source or destination will bypass the user-defined encryption policies.
Cisco has confirmed this vulnerability in a security notice; however, software updates are not available.
To exploit this vulnerability the attacker would likely need access to trusted, internal networks in which the targeted device may reside. Depending on the network configuration, such systems are typically placed behind network security devices, such as firewalls.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
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Customers should refer to Cisco bug ID CSCui07698 for the most complete list of affected product versions.
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Administrators are advised to contact the vendor regarding future updates and releases.
It is critical to prevent unauthorized direct communication to network devices. Restrict network traffic destined for the network infrastructure to protect against reconnaissance and denial of service attacks. For configuration details, see Protecting Your Core: Infrastructure Protection Access Control Lists.
Understanding activity on the network provides information and visibility to help identify potential security incidents. Organizations are advised to log events from devices and review the data to discern anomalies or malicious activity. For logging best practices, see Cisco Guide to Harden Cisco IOS Devices.
To prevent information disclosure and unauthorized access, restrict privileged management access to devices. Apply security features such as Management Plane Protection or Control Plane Protection to the device. For best practices for securing interactive management sessions, see Cisco Guide to Harden Cisco IOS Devices.
Administrators are advised to review the workaround section described in the CSCui07698 bug details.
Administrators are advised to monitor affected systems.
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Software updates are not available.
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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 Release NA Final 2013-Jul-19
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