Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities

Multiple vulnerabilities in the web-based management interface of the Cisco Catalyst Passive Optical Network (PON) Series Switches Optical Network Terminal (ONT) could allow an unauthenticated, remote attacker to perform the following actions:

• Log in with a default credential if the Telnet protocol is enabled
• Perform command injection
• Modify the configuration

Vulnerable Products

These vulnerabilities affect the following Cisco products:

• Catalyst PON Switch CGP-ONT-1P
• Catalyst PON Switch CGP-ONT-4P
• Catalyst PON Switch CGP-ONT-4PV
• Catalyst PON Switch CGP-ONT-4PVC
• Catalyst PON Switch CGP-ONT-4TVCW

Note: By default, the Cisco Catalyst PON Series Switches ONTs allow only local LAN connections to the web management interface. Therefore, all these vulnerabilities are exploitable only via the switches’ LAN ports unless Remote Web Management has been configured.

Devices must be running a vulnerable release and have the Telnet protocol enabled to be affected by the Cisco Catalyst PON Series Switches Optical Network Terminal Telnet Default Credential Vulnerability (CVE-2021-34795).

Note: The Telnet protocol is disabled by default and the default credential works only over Telnet.

Determine the Remote Web Management Configuration

To determine whether the Remote Web Management feature is enabled, navigate to Administration > Device Access Settings and look at the Remote Web Management tab. If the Enable check box is checked, Remote Web Management is enabled on the device.

Determine the Telnet Configuration

To determine whether Telnet access is enabled on the device, navigate to Administration > Device Access Settings and look at the Local Telnet tab. If the Enable check box is checked, Telnet access is enabled on the device.

Details

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