high
8.6
CWE
400 399
CVE Published
Advisory Published
Updated

CVE-2019-1967: Cisco NX-OS Software Network Time Protocol Denial of Service Vulnerability

First published: Thu Aug 29 2019(Updated: )

A vulnerability in the Network Time Protocol (NTP) feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to excessive use of system resources when the affected device is logging a drop action for received MODE_PRIVATE (Mode 7) NTP packets. An attacker could exploit this vulnerability by flooding the device with a steady stream of Mode 7 NTP packets. A successful exploit could allow the attacker to cause high CPU and memory usage on the affected device, which could cause internal system processes to restart or cause the affected device to unexpectedly reload. Note: The NTP feature is enabled by default.

Credit: ykramarz@cisco.com

Affected SoftwareAffected VersionHow to fix
Cisco NX-OS=6.2
Cisco NX-OS=7.3
Cisco NX-OS=8.1
Cisco NX-OS=8.2
Cisco NX-OS=8.3
Cisco MDS 9000 Series Multilayer Switches
Cisco MDS 9100
Cisco MDS 9140
Cisco MDS 9200
Cisco MDS 9500
Cisco MDS 9700
Cisco NX-OS=6.0\(2\)a8\(9.7\)
Cisco NX-OS=6.0\(2\)u6
Cisco NX-OS=7.0\(3\)i
Cisco NX-OS=9.2
Cisco NX-OS=9.2\(1\)
Cisco Nexus 3016Q Firmware
Cisco Nexus 3048 Firmware
Cisco Nexus 3064 Firmware
Cisco Nexus 3064
Cisco Nexus 31108PC-V Firmware
Cisco Nexus 31108TC-V Firmware
Cisco Nexus 31128PQ
Cisco Nexus 3132C-Z Firmware
Cisco Nexus 3132Q-XL
Cisco Nexus 3132Q-V Firmware
Cisco Nexus 3132Q-XL Firmware
Cisco Nexus 3164Q Firmware
Cisco Nexus 3172 Firmware
Cisco Nexus 3172PQ-XL Firmware
Cisco Nexus 3172TQ Firmware
Cisco Nexus 3172TQ-XL
Cisco Nexus 3172TQ-XL Firmware
Cisco Nexus 3232C
Cisco Nexus 3264C-E Firmware
Cisco Nexus 3264Q Firmware
Cisco Nexus 3408-S Firmware
Cisco Nexus 34180YC Firmware
Cisco Nexus 3432D-S Firmware
Cisco Nexus 3464C Firmware
Cisco NX-OS Nexus 9000 Series
Cisco Nexus 92160YC Switch
Cisco Nexus 92300YC Firmware
Cisco Nexus 92304QC Switch
Cisco Nexus 92348GC-X Switch
Cisco Nexus 9236C Switch
Cisco Nexus 9272Q Switch
Cisco Nexus
Cisco Nexus 93108TC-FX Switch
Cisco Nexus 93120TX Firmware
Cisco Nexus 93128 Firmware
Cisco Nexus 93180LC-EX Switch
Cisco Nexus 93180YC-EX-24
Cisco Nexus 93180YC-FX Firmware
Cisco Nexus 93216TC-FX2 Firmware
Cisco Nexus 93240YC-FX2 Firmware
Cisco Nexus 9332C Firmware
Cisco Nexus 9332PQ Firmware
Cisco Nexus 93360YC-FX2
Cisco Nexus 9336C-FX2 Firmware
Cisco Nexus N9336PQ-X
Cisco Nexus 9348GC-FXP Firmware
Cisco Nexus 9364c-h1
Cisco Nexus 9372PX-E
Cisco Nexus 9372PX-E Firmware
Cisco Nexus 9372TX
Cisco Nexus 9372TX-E Switch
Cisco Nexus 9396PX Firmware
Cisco Nexus 9396TX Firmware
Cisco NX-OS=6.0\(2\)a8
Cisco NX-OS=7.0\(3\)i7
Cisco Nexus 3524-xl
Cisco Nexus 3524-xl
Cisco Nexus 3524-XL Firmware
Cisco Nexus 3548-X/XL Firmware
Cisco Nexus 3548-X/XL
Cisco Nexus 3548-X/XL
Cisco NX-OS=7.0\(3\)f
Cisco Nexus 36180YC-R Firmware
Cisco Nexus 3636C-R Firmware
Cisco Nexus 9504 firmware
Cisco Nexus 9508
Cisco Nexus 9516 firmware
Cisco NX-OS=7.1\(4\)
Cisco NX-OS=7.1\(4\)n1\(1\)
Cisco NX-OS=7.1\(5\)
Cisco NX-OS=7.2
Cisco Nexus 5548P Firmware
Cisco Nexus 5548UP Firmware
Cisco Nexus 5596T Firmware
Cisco Nexus 5596UP Firmware
Cisco 56128p
Cisco Nexus 5624Q Firmware
Cisco Nexus 5648Q Firmware
Cisco Nexus 5672UP-16G
Cisco Nexus 5696Q Firmware
Cisco Nexus 6001 Firmware
Cisco Nexus 6004 Firmware
Cisco NX-OS=7.3\(2\)d1\(1\)
Cisco NX-OS=8.0
Cisco NX-OS=8.3\(2\)s5
Cisco Nexus 7000
Cisco Nexus 7000
Cisco Nexus 7000
Cisco Nexus 7000
Cisco Nexus 7000 9-Slot Firmware
Cisco Nexus 7700 series
Cisco Nexus 7700 series
Cisco Nexus 7700 series
Cisco Nexus 7700 series
Cisco Nexus 7700 6-slot

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2019-1967?

    CVE-2019-1967 has been assigned a high severity rating due to its potential to cause a denial of service (DoS) condition.

  • How do I fix CVE-2019-1967?

    To fix CVE-2019-1967, you need to apply the security patches provided by Cisco for affected NX-OS software versions.

  • What versions of Cisco NX-OS are affected by CVE-2019-1967?

    CVE-2019-1967 affects Cisco NX-OS versions 6.2, 7.3, 8.1, 8.2, 8.3 and several other specific releases.

  • What are the potential impacts of CVE-2019-1967?

    Successful exploitation of CVE-2019-1967 can lead to exhaustion of system resources, resulting in a denial of service for the affected device.

  • Is there a workaround for CVE-2019-1967?

    Cisco recommends disabling the NTP service if it is not needed as a temporary workaround for CVE-2019-1967.

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