Headline
CVE-2023-20124: Cisco Security Advisory: Cisco Small Business RV016, RV042, RV042G, RV082, RV320, and RV325 Routers Remote Command Execution Vulnerability
A vulnerability in the web-based management interface of Cisco Small Business RV016, RV042, RV042G, RV082, RV320, and RV325 Routers could allow an authenticated, remote attacker to execute arbitrary commands on an affected device. This vulnerability is due to improper validation of user input within incoming HTTP packets. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web-based management interface. A successful exploit could allow the attacker to gain root-level privileges and access unauthorized data. To exploit this vulnerability, an attacker would need to have valid administrative credentials on the affected device. Cisco has not released software updates that address this vulnerability.
There are no workarounds that address this vulnerability. However, administrators can mitigate this vulnerability by either disabling remote management or blocking access to ports 443 and 60443, depending on the hardware platform. The routers will still be accessible through the LAN interface after the mitigation has been implemented.
Disable Remote Management for Cisco RV320 and RV325 Routers
To disable remote management, do the following:
- Log in to the web-based management interface for the device.
- Choose Firewall > General.
- Uncheck the Remote Management check box.
Block Access to Ports 443 and 60443 for Cisco RV016, RV042, RV042G and RV082 Routers
First, add a new service to the access rules of the device for port 60443. It is not necessary to create a service for port 443 because it is predefined in the services list.
- Log in to the web-based management interface for the device.
- Choose Firewall > Access Rules.
- Click Service Management.
- In the Service Name field, enter TCP-60443.
- From the Protocol drop-down list, choose TCP.
- In both of the Port Range fields, enter 60443.
- Click Add to List.
- Click OK.
Next, create access rules to block ports 443 and 60443. To create an access rule to block port 443, do the following:
- Log in to the web-based management interface for the device.
- Choose Firewall > Access Rules.
- Click Add.
- From the Action drop-down list, choose Deny.
- From the Service drop-down list, choose HTTPS (TCP 443-443).
- From the Log drop-down list, choose Log packets match this rule.
- From the Source Interface drop-down list, choose the option that matches the WAN connection on the device.
- From the Source IP drop-down list, choose Any.
- From the Destination IP drop-down list, choose Single.
- In both of the Destination IP fields, enter the WAN IP address.
- Click Save.
To create an access rule to block port 60443, repeat the preceding steps, but for Step 5, choose HTTPS (TCP 60443-60443) from the Service drop-down list.
Note: If a second WAN port is being used, two additional ACL rules need to be set up using the WAN number and IP address for the second WAN port.
While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.