Cisco IOS XR Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are not available.
A vulnerability in the SNMP process on Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a reload of the affected process and a limited memory leak that affects the process.
The vulnerability is due to not freeing allocated memory. An attacker could exploit this vulnerability by sending a large number of UDP packets to SNMP port 162 on the affected device. An exploit could allow the attacker to cause a limited memory leak that affects only the SNMP process. The attacker could also cause a repeated reload of the affected process.
Cisco has confirmed the vulnerability in a security notice; however, software updates are not available.
At the time this alert was first published, Cisco IOS XR Software version 4.3.0 was vulnerable. Later versions of Cisco IOS XR may also be affected.
To exploit this vulnerability, an attacker may require access to trusted, internal networks to send crafted requests to the affected software. This access requirement could limit 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 cause a limited memory leak that affects only the SNMP process. The attacker could also cause a repeated reload of the affected process.
Additional technical details are unavailable.
Administrators are advised to contact the vendor regarding future updates and releases.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
Understanding activity on the network provides information and visibility that can be used to identify potential security incidents. Organizations should log events from devices and review the logged data to provide insight into anomalies or malicious activity. For logging best practices, see Cisco Guide to Harden Cisco IOS Devices.
Customers who wish to upgrade to a software version that includes fixes for these issues should contact their normal support channels. Free software updates will not be provided for issues that are disclosed through a Cisco Security Notice. Cisco customers can contact 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 security vulnerability applies to the following combinations of products.
Cisco IOS XR Software
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.