Cisco NX-OS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
A vulnerability in the Border Gateway Protocol (BGP) code of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause the affected device to reload.
The vulnerability is due to an issue with the regex engine used when processing complex regular expressions. An attacker could exploit this vulnerability by injecting specific autonomous system (AS) path sets. If the affected device has a complex regular expression applied to the inbound routes, the vulnerability may be triggered. An exploit could allow the attacker to trigger Cisco NX-OS Software to restart.
Cisco has confirmed the vulnerability in a security notice and released software updates.
At the time this alert was first published, Cisco NX-OS Software versions 6.1(3) and prior were vulnerable. Later releases of Cisco NX-OS Software may also be vulnerable.
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-2013-1121
Customers are advised to consult Cisco bug ID CSCuf49554 for the most complete list of affected product versions.
An unauthenticated, remote attacker could exploit this vulnerability to cause an affected device to reload, resulting in a denial of service (DoS) condition.
The vulnerability is due to improper processing of complex regular expressions by the regex engine used by the affected software.
An unauthenticated, remote attacker could exploit this vulnerability by injecting AS path sets. If the affected device has a complex regular expression applied to the inbound routes, the targeted device could reload, resulting in a DoS condition.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to allow only privileged users to access administration or management systems.
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 email@example.com for assistance.
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.