Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated remote attacker to cause a DoS condition.
The vulnerability is due to improper handling of specific L2TP packets by Cisco 1000 ASR. An attacker could exploit this vulnerability by sending a large number of specific L2TP packets to a vulnerable system; this vulnerability cannot be triggered by L2TP traffic transiting a vulnerable device.
A successful exploit could allow the attacker to cause a system to reload, resulting in a DoS condition. Repeated exploitation could result in a sustained DoS condition.
Cisco confirmed the vulnerability in a security advisory and released updated software.
Cisco ASR 1000 Series Aggregation Services Routers running affected releases of Cisco IOS XE Software are affected by this vulnerability.
Cisco has published a list of affected Cisco IOS XE Software releases in the security advisory. The "Vendor Announcements" section of this alert contains a link to the advisory.
To exploit this vulnerability, an attacker may need access to a trusted, internal network to send a series of specific L2TP packets to a vulnerable system. This access requirement may reduce 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.
An unauthenticated, remote attacker could exploit this vulnerability to reload the Embedded Services Processors (ESP) card or Route Processor (RP) card on a targeted device, resulting in a DoS condition. Repeated exploitation could result in a sustained DoS condition.
The vulnerability is due to improper handling of specific L2TP packets by Cisco devices running the affected software. The vulnerability cannot be triggered by L2TP traffic transiting a vulnerable device.
An unauthenticated, remote attacker could exploit this vulnerability by sending a large number of specific L2TP packets to a vulnerable system. If successful, the attacker could cause the targeted device to 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 monitor affected systems.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at email@example.com.
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.