CVE-2021-40112: Cisco Security Advisory: Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities

The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit another vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerabilities.

Details about the vulnerabilities are as follows:

CVE-2021-34795: Cisco Catalyst PON Series Switches Optical Network Terminal Telnet Default Credential Vulnerability

A vulnerability in the Telnet service of Cisco Catalyst PON Series Switches ONT could allow an unauthenticated, remote attacker to log in to the affected device by using a debugging account that has a default, static password.

This vulnerability is due to an unintentional debugging credential that exists on the device. An attacker could exploit this vulnerability by establishing a Telnet session to the device and logging in with the default credential. A successful exploit could allow the attacker to take complete control of the device. The device must be configured to allow Telnet connections. Telnet is not enabled by default.

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

Bug ID(s): CSCvz67097
CVE ID: CVE-2021-34795
Security Impact Rating (SIR): Critical
CVSS Base Score: 10.0
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVE-2021-40113: Cisco Catalyst PON Series Switches Optical Network Terminal Unauthenticated Command Injection Vulnerability

A vulnerability in the web-based management interface of the Cisco Catalyst PON Series Switches ONT could allow an unauthenticated, remote attacker to perform a command injection attack against an affected device.

This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a crafted request to the web-based management interface. A successful exploit could allow the attacker to execute arbitrary commands on an affected device as the root user.

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

Bug ID(s): CSCvz61948
CVE ID: CVE-2021-40113
Security Impact Rating (SIR): Critical
CVSS Base Score: 10.0
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H

CVE-2021-40112: Cisco Catalyst PON Series Switches Optical Network Terminal Unauthenticated Configuration Modification Vulnerability

A vulnerability in the web management interface of the Cisco Catalyst PON Series Switches ONT could allow an unauthenticated, remote attacker to modify the configuration of the device.

This vulnerability is due to improper HTTPS input validation. An attacker could exploit this vulnerability by sending a crafted HTTPS request to the web management interface. A successful exploit could allow the attacker to modify the configuration.

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

Bug ID(s): CSCvz61943
CVE ID: CVE-2021-40112
Security Impact Rating (SIR): High
CVSS Base Score: 8.6
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H

Cisco has released free software updates that address the vulnerabilities described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.

Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html

Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.

The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.

When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.

In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

Customers Without Service Contracts

Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html

Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.

Fixed Releases

In the following table(s), the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerabilities described in this advisory and the first release that includes the fix for these vulnerabilities. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.

Catalyst PON Switch CGP-ONT-1P

Cisco Catalyst PON Series Switches ONT

First Fixed Release for These Vulnerabilities

1.1

1.1.1.14

Catalyst PON Switches CGP-ONT-4P, CGP-ONT-4PV, CGP-ONT-4PVC, and CGP-ONT-4TVCW

Cisco Catalyst PON Series Switches ONT

First Fixed Release for These Vulnerabilities

1.1

1.1.3.17

To download the software from the Software Center on Cisco.com, do the following:

1. Click Browse all.
2. Choose Switches > Campus LAN Switches - Access > Catalyst PON Series.
3. Choose a specific product from the right pane of the product selector.
4. Choose a hardware platform from the left pane of the product’s software page.
5. Download the software.

The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.