Vulnerability Alert

Cisco IOS XE Software IPv6 and MVPNv6 Multicast Traffic Denial of Service Vulnerability

 
Threat Type:CWE-119: Buffer Errors
IntelliShield ID:28814
Version:2
First Published:2013 April 10 16:22 GMT
Last Published:2013 April 18 13:48 GMT
Port: Not available
CVE:CVE-2013-1164 , CVE-2013-2779
Urgency:Unlikely Use
Credibility:Confirmed
Severity:Mild Damage
CVSS Base:7.8 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:6.4
 
Version Summary:IntelliShield has updated this alert to add an additional CVE identifier to reflect multiple denial of service vulnerabilities in Cisco IOS XE Software.
 
 
Description
Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted device.

The vulnerability is due to improper handling of fragmented IPv6 traffic by the Cisco 1000 Series ASR with ASR1000-ESP40 or ASR1000-ESP100. An unauthenticated, remote attacker could exploit this vulnerability by sending fragmented IPv6 packets either traversing or destined to a vulnerable device. A successful exploit could allow the attacker to cause a device to reload abnormally, resulting in a DoS condition. Repeated exploitation could result in a sustained DoS condition.

Cisco has confirmed the vulnerability in a security advisory and has released software updates.
 
Warning Indicators
Cisco IOS XE Software Releases 3.4, 3.5, 3.6, and 3.7 are affected.
 
IntelliShield Analysis
To exploit this vulnerability, an attacker must have 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.
 
Vendor Announcements
Cisco has released a security advisory for bug IDs CSCtz97563 and CSCub34945 at the following link: cisco-sa-20130410-asr1000
 
Impact
An unauthenticated, remote attacker could exploit this vulnerability to cause a device to reload abnormally, resulting in a DoS condition. Repeated exploitation could result in a sustained DoS condition.
 
Technical Information
The vulnerability is due to improper handling of fragmented IPv6 MVPN or fragmented IPv6 multicast traffic by the Cisco 1000 Series ASR with ASR1000-ESP40 or ASR1000-ESP100.

An unauthenticated, remote attacker could exploit this vulnerability by sending fragmented IPv6 MVPN or fragmented IPv6 multicast packets either traversing or destined to a vulnerable device. A successful exploit could allow the attacker to cause a device to reload abnormally, resulting in a DoS condition. Repeated exploitation could result in a sustained DoS condition.
 
Safeguards
Administrators are advised to apply the appropriate updates.

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.

It is critical to prevent unauthorized direct communication to network devices. Restrict network traffic destined for the network infrastructure to protect against reconnaissance and DoS attacks. For configuration details, see Protecting Your Core: Infrastructure Protection Access Control Lists.

Network traffic should be monitored for security-related network activity. Cisco NetFlow identifies security-related network activity. For NetFlow configuration details, see Introduction to Cisco IOS NetFlow - A Technical Overview.

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.

Administrators are advised to monitor affected systems.
 
Patches/Software
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 tac@cisco.com
 
Alert History
 

Version 1, April 10, 2013, 4:22 PM: Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition on a targeted device. Updates are available.



Product Sets
 
The security vulnerability applies to the following combinations of products.

Primary Products:
CiscoCisco IOS XE Software 3.4S .0, .1 | 3.5S Base | 3.6S Base | 3.7S Base, .0

Associated Products:
N/A




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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.
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