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Vulnerability Alert

Cisco IOS and IOS XE Software Internet Key Exchange Processing Denial of Service Vulnerability

 
Threat Type:CWE-399: Resource Management Errors
IntelliShield ID:30696
Version:1
First Published:2013 September 25 16:27 GMT
Last Published:2013 September 25 16:27 GMT
Port: Not available
CVE:CVE-2013-5473
Urgency:Unlikely Use
Credibility:Confirmed
Severity:Mild Damage
CVSS Base:7.8 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:6.4
 
Version Summary:Cisco IOS and IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
 
 
Description
A vulnerability in the Internet Key Exchange (IKE) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.

The vulnerability is due to improper handling of crafted IKE packets by the affected software. An attacker could exploit this vulnerability by sending crafted IKE packets to a device configured with features that leverage IKE version 1 (IKEv1). A successful exploit could cause Cisco IOS Software not to release allocated memory, causing a memory leak. A sustained attack may result in a device reload, resulting in a DoS condition for legitimate users.

Cisco has confirmed the vulnerability in a security advisory and released software updates.
 
Warning Indicators
Cisco devices that are running Cisco IOS Software or Cisco IOS-XE Software are vulnerable when they are configured to use IKEv1 or IKE version 2 (IKEv2).

Cisco has published a list of affected Cisco IOS Software releases in the security advisory. The Vendor Announcements section of this alert contains a link to the advisory.
 
IntelliShield Analysis
To exploit this vulnerability, the attacker would need the ability to send malformed IKEv1 packets to the targeted system. To achieve this objective, the attacker may need access to trusted, internal network resources in which the targeted device may reside. This access requirement reduces the likelihood of a successful exploit.

Although IKEv1 is automatically enabled on Cisco IOS Software and Cisco IOS XE Software when IKEv1 or IKEv2 is configured, the vulnerability can be triggered only by sending a malformed IKEv1 packet; however in specific conditions, normal IKEv1 packets can also cause an affected release of Cisco IOS Software to leak memory.

Only IKEv1 is affected by this vulnerability.

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 Cisco bug ID CSCtx66011 at the following link: cisco-sa-20130925-ike
 
Impact
An unauthenticated, remote attacker could exploit this vulnerability to cause a memory leak in the affected software, resulting in a DoS condition.
 
Technical Information
The vulnerability is due to incorrect handling of malformed IKE packets by the affected software.

An unauthenticated, remote attacker could exploit this vulnerability by sending malformed IKEv1 packets via UDP ports 500, 848, or 4500 to an affected device. Processing the malformed IKEv1 packets could trigger a memory leak on an affected device, resulting in a DoS condition.
 
Safeguards
Administrators are advised to apply the appropriate updates.

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

Administrators are advised to allow only trusted users to have network access.

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
 
Initial Release


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

Primary Products:
CiscoIOS 15.1M 15.1(4)M3, 15.1(4)M3a, 15.1(4)M4 | 15.1MR 15.1(3)MR | 15.1S 15.1(3)S2, 15.1(3)S3, 15.1(3)S4, 15.1(3)S5, 15.1(3)S5a | 15.1XB 15.1(4)XB7, 15.1(4)XB8a | 15.2GC 15.2(3)GC | 15.2GCA 15.2(3)GCA | 15.2S 15.2(2)S | 15.2T 15.2(3)T, 15.2(3)T1, 15.2(3)T2 | 15.2XA 15.2(3)XA
CiscoCisco IOS XE Software 3.4S .2, .3, .4, .5 | 3.6S Base, .0

Associated Products:
N/A




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LEGAL DISCLAIMER
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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