Cisco patches serious vulnerabilities in small business RV Series routers

Cisco Systems released patches for its small business RV Series routers and firewalls to address vulnerabilities that could allow attackers to execute arbitrary commands and overwrite files on the vulnerable devices.

The affected products are Cisco RV120W Wireless-N VPN Firewall, Cisco RV180 VPN Router, Cisco RV180W Wireless-N Multifunction VPN Router, and Cisco RV220W Wireless Network Security Firewall. However, firmware updates have been released only for the first three models, while the fixes for Cisco RV220W are expected later this month.

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One of the patched flaws allows an attacker to execute arbitrary commands as root — the highest privileged account — through the network diagnostics page in a device’s Web-based administration interface. The flaw stems from improper input validation in a form field that’s supposed to only allow the PING command. Its exploitation requires an authenticated session to the router interface.

A second vulnerability allows attackers to execute cross-site request forgery (CSRF) attacks against users who are already authenticated on the devices. Attackers can piggyback on their authenticated browser sessions to perform unauthorized actions if they can trick those users to click on specially crafted links.

This vulnerability also provides a way to remotely exploit the first flaw. Researchers from Dutch security firm Securify, who found both issues, published a proof-of-concept URL that leverages the CSRF flaw to inject a command through the first vulnerability that adds a rogue administrator account on the targeted device.

A third security flaw that was patched by Cisco allows an unauthenticated attacker to upload files to arbitrary locations on a vulnerable device using root privileges. Existing files will be overwritten, the Securify researchers said.

Cisco released firmware versions 1.0.4.14 for the RV180 and RV180W models and firmware version 1.0.5.9 for the RV120W.

Users can limit the exposure of their devices to these flaws by not allowing remote access from the Internet to their administrative interfaces. If remote management is required, the Web Access configuration screen on the devices can be used to restrict access only to specific IP addresses, Cisco said in its advisory.