Cisco has published a Security Advisory regarding a Critical Remote Code Execution vulnerability affecting several Cisco Small Business Routers.
The vulnerability is remotely exploitable without requiring authentication and allows attackers to remotely execute commands and arbitrary code or to trigger a denial-of-service on vulnerable devices.
- CVE-2021-34730 (CVSS 3.1: 9.8, Critical)
A vulnerability in the Universal Plug-and-Play (UPnP) service of Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers could allow an unauthenticated, remote attacker to execute arbitrary code or cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition.
- RV110W Wireless-N VPN Firewalls
- RV130 VPN Routers
- RV130W Wireless-N Multifunction VPN Routers
- RV215W Wireless-N VPN Routers
The vulnerability only affects these devices if they have UPnP Enabled.
Cisco has not released and will not release software updates to address the vulnerability, as the vulnerable products have reached their end-of-life and it is recommended to upgrade to newer devices.
However, Disabling UPnP mitigates the risk.
The UPnP service is enabled by default on LAN interfaces and disabled by default on WAN interfaces. If UPnP is disabled on both the LAN and WAN interfaces, the device is not considered vulnerable.
To disable UPnP on the LAN interface of a device, do the following:
- Open the web-based management interface and choose Basic Settings > UPnP.
- Check the ‘Disable’ check box.
For more information regarding the vulnerability and mitigation procedure, visit the Cisco Security Advisory.
References: Cisco Security Advisories