Cisco NX-OS Software system login block-for Denial of Service Vulnerability

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.

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

This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Medium

CVE: CVE-2021-1590

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Cisco UCS Manager Software SSH Sessions Denial of Service Vulnerability

A vulnerability in the way Cisco UCS Manager software handles SSH sessions could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to improper resource management for established SSH sessions. An attacker could exploit this vulnerability by opening a significant number of SSH sessions on an affected device. A successful exploit could allow the attacker to cause a crash and restart of internal Cisco UCS Manager software processes and a temporary loss of access to the Cisco UCS Manager CLI and web UI.

Note: The attacker must have valid user credentials to authenticate to the 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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-dos-MgvmyrQy

This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Medium

CVE: CVE-2021-1592

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Cisco Nexus 9500 Series Switches Access Control List Bypass Vulnerability

A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthenticated, remote attacker to bypass access control list (ACL) rules that are configured on an affected device.

This vulnerability is due to oversubscription of resources that occurs when applying ACLs to port channel interfaces. An attacker could exploit this vulnerability by attempting to access network resources that are protected by the ACL. A successful exploit could allow the attacker to access network resources that would be protected by the ACL that was applied on the port channel interface.

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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nexus-acl-vrvQYPVe

This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Medium

CVE: CVE-2021-1591

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Cisco Nexus 9000 Series Fabric Switches ACI Mode Privilege Escalation Vulnerability

A vulnerability in Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an authenticated, local attacker to elevate privileges on an affected device.

This vulnerability is due to insufficient restrictions during the execution of a specific CLI command. An attacker with administrative privileges could exploit this vulnerability by performing a command injection attack on the vulnerable command. A successful exploit could allow the attacker to access the underlying operating system as root

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: 
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-naci-mdvul-vrKVgNU

This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Medium

CVE: CVE-2021-1584

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Cisco Nexus 9000 Series Fabric Switches ACI Mode Arbitrary File Read Vulnerability

A vulnerability in the fabric infrastructure file system access control of Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an authenticated, local attacker to read arbitrary files on an affected system.

This vulnerability is due to improper access control. An attacker with Administrator privileges could exploit this vulnerability by executing a specific vulnerable command on an affected device. A successful exploit could allow the attacker to read arbitrary files on the file system of the 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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-naci-afr-UtjfO2D7

This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Medium

CVE: CVE-2021-1583

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Cisco Nexus 9000 Series Fabric Switches ACI Mode Queue Wedge Denial of Service Vulnerability

A vulnerability in Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, remote attacker to cause a queue wedge on a leaf switch, which could result in critical control plane traffic to the device being dropped. This could result in one or more leaf switches being removed from the fabric.

This vulnerability is due to mishandling of ingress TCP traffic to a specific port. An attacker could exploit this vulnerability by sending a stream of TCP packets to a specific port on a Switched Virtual Interface (SVI) configured on the device. A successful exploit could allow the attacker to cause a specific packet queue to queue network buffers but never process them, leading to an eventual queue wedge. This could cause control plane traffic to be dropped, resulting in a denial of service (DoS) condition where the leaf switches are unavailable.

Note: This vulnerability requires a manual intervention to power-cycle the device to recover.

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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n9kaci-queue-wedge-cLDDEfKF

This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: High

CVE: CVE-2021-1523

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Cisco NX-OS Software Unauthenticated Arbitrary File Actions Vulnerability

A vulnerability in the implementation of an internal file management service for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode that are running Cisco NX-OS Software could allow an unauthenticated, remote attacker to create, delete, or overwrite arbitrary files with root privileges on the device.  

This vulnerability exists because TCP port 9075 is incorrectly configured to listen and respond to external connection requests. An attacker could exploit this vulnerability by sending crafted TCP packets to an IP address that is configured on a local interface on TCP port 9075. A successful exploit could allow the attacker to create, delete, or overwrite arbitrary files, including sensitive files that are related to the device configuration. For example, the attacker could add a user account without the device administrator knowing.

Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-3000-9000-fileaction-QtLzDRy2

This advisory is part of the February 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: February 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Critical

CVE: CVE-2021-1361

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Cisco NX-OS Software NX-API Cross-Site Request Forgery Vulnerability

A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to conduct a cross-site request forgery (CSRF) attack on an affected system.

This vulnerability is due to insufficient CSRF protections for the NX-API on an affected device. An attacker could exploit this vulnerability by persuading a user of the NX-API to follow a malicious link. A successful exploit could allow the attacker to perform arbitrary actions with the privilege level of the affected user. The attacker could view and modify the device configuration.

Note: The NX-API feature is disabled by default.

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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-nxapi-csrf-wRMzWL9z

This advisory is part of the February 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: February 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: High

CVE: CVE-2021-1227

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Cisco NX-OS Software CLI Arbitrary Command Injection Vulnerability

A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker to perform a command-injection attack on an affected device.

The vulnerability is due to insufficient input validation of command arguments. An attacker could exploit this vulnerability by injecting malicious command arguments into a vulnerable CLI command. A successful exploit could allow the attacker, authenticated as a privileged user, to execute arbitrary commands with root privileges.

Note: On products that support multiple virtual device contexts (VDC), this vulnerability could allow an attacker to access files from any VDC.

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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nx-os-cli-injection

This advisory is part of the June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection, which includes 24 Cisco Security Advisories that describe 24 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.

Security Impact Rating: High

CVE: CVE-2018-0307

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Cisco NX-OS Software CLI Arbitrary Command Execution Vulnerability

A vulnerability in the CLI parser of Cisco NX-OS Software could allow an authenticated, local attacker to perform a command-injection attack on an affected device.

The vulnerability is due to insufficient input validation of command arguments. An attacker could exploit this vulnerability by injecting malicious command arguments into a vulnerable CLI command. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the affected device.

Note: This vulnerability requires that any feature license is uploaded to the device. The vulnerability does not require that the license be used.

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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nx-os-cli-execution

This advisory is part of the June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection, which includes 24 Cisco Security Advisories that describe 24 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.

Security Impact Rating: High

CVE: CVE-2018-0306

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