Cisco Security Advisory: Cisco NX-OS Software TCP Netstack Denial of Service Vulnerability

[Cisco Systems Product Security Incident Response Team <psirt@xxxxxxxxx>]

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Cisco NX-OS Software TCP Netstack Denial of Service Vulnerability

Advisory ID: cisco-sa-20160302-netstack

Revision 1.0

For Public Release 2016 March 02 16:00  UTC (GMT) 

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Summary
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A vulnerability in the TCP stack of Cisco NX-OS Software could allow an 
unauthenticated, remote attacker to cause a denial of service (DoS) condition.

The vulnerability is due to improper processing of certain TCP packets in the 
closing sequence of a TCP session while the affected device is in a TIME_WAIT 
state. An attacker could exploit this vulnerability by sending a specific TCP 
packet to an affected device on a TCP session that is already in a TIME_WAIT 
state. An exploit could allow the attacker to cause a reload of the TCP stack 
on the affected device, resulting in a DoS condition.

This vulnerability can be exploited using either IPv4 or IPv6 packets. The 
vulnerability can be triggered by a crafted sequence of TCP packets destined 
for TCP ports listening on the device. The packets may use the IPv4 or IPv6 
unicast address of any interface configured on the device.

This vulnerability can be triggered only by traffic destined to an affected 
device and cannot be exploited using traffic that transits an affected device.

Cisco has released software updates that address this vulnerability. There are 
no workarounds that address this vulnerability.

This advisory is available at the following link:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160302-netstack

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