Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to bypass security restrictions. Updates are available.
A vulnerability in the vty authentication of Cisco IOS XE Software (03.02.xxSE and 03.03.xxSE only) could allow an unauthenticated, remote attacker to access an affected device without authentication and perform actions on the device with the privileges configured for the vty line interface.
The vulnerability is due to incomplete validations of the Linux-IOS Internal Network interface. An unauthenticated, remote attacker could exploit this vulnerability only if their source address is in the 192.168.x.2 subnet and the attacker has IP communication to the Cisco IOS XE device. An exploit could allow the attacker to access the device with the privilege level of the vty line interface.
Cisco has confirmed the vulnerability in a security notice and released software updates.
At the time this alert was first published, Cisco IOS XE Software version 3.3SE (.0) and prior were vulnerable. Later releases of Cisco IOS XE Software may also be vulnerable.
To exploit this vulnerability, it is likely that an attacker would need access to trusted, internal networks in order to communicate with the targeted device. This access requirement limits the likelihood of a successful exploit.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
Cisco has released a security notice at the following link: CVE-2013-6979
Customers are advised to consult Cisco bug ID CSCuj90227 for the most complete list of affected product versions.
An unauthenticated, remote attacker to access an affected device with the privilege level of the VTY line interface. A successful exploit could be used to conduct further attacks.
The vulnerability is due to incomplete validations of the Linux-IOS Internal Network interface on an affected device.
An unauthenticated, remote attacker could exploit this vulnerability only if their source address is in the 192.168.x.2 subnet and the attacker has IP communication to the Cisco IOS XE device. An exploit could allow the attacker to access an affected device with the privilege level of the VTY line interface.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only privileged users to access administration or management systems.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts should contact their Cisco support team for assistance in upgrading to a software version that includes fixes for this vulnerability. Cisco customers without contracts may contact the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at firstname.lastname@example.org for assistance.
The security vulnerability applies to the following combinations of products.
Cisco IOS XE Software
3.2SE .0, .1, .2, .3 | 3.3SE .0, .1
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