Cisco NX-OS Software TCP Vulnerability

A vulnerability in the Transmission Control Protocol (TCP) stack of the Cisco NX-OS software may allow a remote, unauthenticated attacker to cause a denial-of-service (DoS) condition.

Threat ID:: CC-1857
Category:
Threat Severity:: Medium
Threat Vector:
Published:: 14 December 2017 12:00 AM

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Summary

A vulnerability in the Transmission Control Protocol (TCP) stack of the Cisco NX-OS software may allow a remote, unauthenticated attacker to cause a denial-of-service (DoS) condition.

Affected platforms

The following platforms are known to be affected:

Cisco Nexus Fabric Switches

Cisco Nexus 1000V Series Switches
Cisco Nexus 3000 Series Switches
Cisco Nexus 4000 Series Switches
Cisco Nexus 5000 Series Switches
Cisco Nexus 6000 Series Switches
Cisco Nexus 7000 Series Switches
Cisco Unified Computing System (UCS) running Cisco NX-OS

Threat details

Improper processing of specific TCP packets during the close sequence of a session, when a device moves to a TIME_WAIT state, can be exploited by an attacker sending new packets from another session that is already in the TIME_WAIT state. This causes the device to reload its TCP stack, resulting in a DoS condition.

The vulnerability can only be triggered by traffic destined to an affected device and not from traffic that transits it. Both IPv4 and IPv6 packets can be used.

Remediation steps

Type	Step
	Administrators must apply the necessary updates. These can be found here.

Last edited: 17 February 2020 11:28 am