CVE-2021-1590: Cisco NX-OS Software system login block-for Denial of Service Vulnerability

First published: Wed Aug 25 2021(Updated: )

A vulnerability in the implementation of the system login block-for command for Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a login process to unexpectedly restart, causing a denial of service (DoS) condition. This vulnerability is due to a logic error in the implementation of the system login block-for command when an attack is detected and acted upon. An attacker could exploit this vulnerability by performing a brute-force login attack on an affected device. A successful exploit could allow the attacker to cause a login process to reload, which could result in a delay during authentication to the affected device.

Credit: ykramarz@cisco.com

Affected Software	Affected Version	How to fix
Cisco Nx-os	=7.0\(3\)i4\(0.116\)
Cisco Nx-os	=7.3\(7\)n1\(1b\)
Cisco Nexus 3000
Cisco Nexus 3048
Cisco Nexus 31108pc-v
Cisco Nexus 31108tc-v
Cisco Nexus 31128pq
Cisco Nexus 3132c-z
Cisco Nexus 3132q-v
Cisco Nexus 3132q-x\/3132q-xl
Cisco Nexus 3164q
Cisco Nexus 3172pq\/pq-xl
Cisco Nexus 3172tq-xl
Cisco Nexus 3232c
Cisco Nexus 3264c-e
Cisco Nexus 3264q
Cisco Nexus 3408-s
Cisco Nexus 34180yc
Cisco Nexus 3432d-s
Cisco Nexus 3464c
Cisco Nexus 3524-x\/xl
Cisco Nexus 3548-x\/xl
Cisco Nexus 36180yc-r
Cisco Nexus 3636c-r
Cisco Nexus 5548p
Cisco Nexus 5548up
Cisco Nexus 5596t
Cisco Nexus 5596up
Cisco Nexus 56128p
Cisco Nexus 5624q
Cisco Nexus 5648q
Cisco Nexus 5672up
Cisco Nexus 5672up-16g
Cisco Nexus 5696q
Cisco Nexus 6001
Cisco Nexus 6004
Cisco Nexus 7000 10-slot
Cisco Nexus 7000 18-slot
Cisco Nexus 7000 4-slot
Cisco Nexus 7000 9-slot
Cisco Nexus 7000 Supervisor 1
Cisco Nexus 7000 Supervisor 2
Cisco Nexus 7000 Supervisor 2e
Cisco Nexus 7004
Cisco Nexus 7009
Cisco Nexus 7010
Cisco Nexus 7018
Cisco Nexus 7700
Cisco Nexus 7700 10-slot
Cisco Nexus 7700 18-slot
Cisco Nexus 7700 2-slot
Cisco Nexus 7700 6-slot
Cisco Nexus 7700 Supervisor 2e
Cisco Nexus 7700 Supervisor 3e
Cisco Nexus 7702
Cisco Nexus 7706
Cisco Nexus 7710
Cisco Nexus 7718
Cisco Nexus 9000v
Cisco Nexus 92160yc-x
Cisco Nexus 92300yc
Cisco Nexus 92304qc
Cisco Nexus 92348gc-x
Cisco Nexus 9236c
Cisco Nexus 9272q
Cisco Nexus 93108tc-ex
Cisco Nexus 93108tc-ex-24
Cisco Nexus 93108tc-fx
Cisco Nexus 93108tc-fx-24
Cisco Nexus 93108tc-fx3p
Cisco Nexus 93120tx
Cisco Nexus 93128tx
Cisco Nexus 9316d-gx
Cisco Nexus 93180lc-ex
Cisco Nexus 93180yc-ex
Cisco Nexus 93180yc-ex-24
Cisco Nexus 93180yc-fx
Cisco Nexus 93180yc-fx-24
Cisco Nexus 93180yc-fx3
Cisco Nexus 93180yc-fx3s
Cisco Nexus 93216tc-fx2
Cisco Nexus 93240yc-fx2
Cisco Nexus 9332c
Cisco Nexus 9332pq
Cisco Nexus 93360yc-fx2
Cisco Nexus 9336c-fx2
Cisco Nexus 9336c-fx2-e
Cisco Nexus 9348gc-fxp
Cisco Nexus 93600cd-gx
Cisco Nexus 9364c
Cisco Nexus 9364c-gx
Cisco Nexus 9372px
Cisco Nexus 9372px-e
Cisco Nexus 9372tx
Cisco Nexus 9372tx-e
Cisco Nexus 9396px
Cisco Nexus 9396tx
Cisco Nexus 9508
Cisco Unified Computing System	<4.0\(4m\)
Cisco Unified Computing System	>=4.1<4.1\(3d\)
Cisco Unified Computing System 6248up
Cisco Unified Computing System 6296up
Cisco Unified Computing System 6324
Cisco Unified Computing System 6332
Cisco Unified Computing System 6332-16up

Remedy

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-login-blockfor-RwjGVEcu

Never miss a vulnerability like this again

Reference Links

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-login-blockfor-RwjGVEcu

CVE-2021-1590: Cisco NX-OS Software system login block-for Denial of Service Vulnerability

Remedy

Never miss a vulnerability like this again

Reference Links

Company

Resources

Contact