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 SIP packets by Cisco 1000 Series ASR when configured for VRF-aware NAT and SIP ALG. An attacker could exploit this vulnerability by sending a large number of SIP packets traversing a device configured for NAT; this vulnerability cannot be triggered by SIP traffic destined to 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 versions 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 large number of SIP packets through 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 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 SIP packets by Cisco 1000 Series ASR devices when configured for NAT. The vulnerability can be triggered by sending SIP traffic that will traverse a vulnerable device.
An unauthenticated, remote attacker could exploit this vulnerability by sending a large number of SIP packets traversing a NAT on a vulnerable system. If successful, the attacker could cause a 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 firstname.lastname@example.org.
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.