Multiple Flaws in Cisco Small Business Routers Allow Remote Attackers to Execute Arbitrary Code

Cisco has released software updates that address multiple vulnerabilities in Cisco Small Business VPN routers which allow an unauthenticated, remote attacker to execute arbitrary code or cause a denial of service (DoS) condition on an affected device.

Vulnerable Products

The vulnerabilities tracked as CVE-2022-20827 and CVE-2022-20841 affect the following Cisco products:

• RV160 VPN Routers
• RV160W Wireless-AC VPN Routers
• RV260 VPN Routers
• RV260P VPN Routers with PoE
• RV260W Wireless-AC VPN Routers
• RV340 Dual WAN Gigabit VPN Routers
• RV340W Dual WAN Gigabit Wireless-AC VPN Routers
• RV345 Dual WAN Gigabit VPN Routers
• RV345P Dual WAN Gigabit POE VPN Routers

The vulnerability tracked as CVE-2022-20842 affects the following Cisco products:

• RV340 Dual WAN Gigabit VPN Routers
• RV340W Dual WAN Gigabit Wireless-AC VPN Routers
• RV345 Dual WAN Gigabit VPN Routers
• RV345P Dual WAN Gigabit POE VPN Routers

In an advisory, Cisco noted that “The vulnerabilities are dependent on one another. Exploitation of one of the vulnerabilities may be 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”.

Cisco Small Business RV Series Routers Remote Code Execution and Denial of Service Vulnerability:

The flaw is tracked as (CVE-2022-20842) with the CVSS Base Score: 9.8, found in the web-based management interface of Cisco RV340, RV340W, RV345, and RV345P Dual WAN Gigabit VPN Routers.

Upon successful exploitation of the vulnerability could allow an attacker to execute arbitrary code or cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. An attacker could exploit this vulnerability by sending crafted HTTP input to an affected device.

The advisory mention that “The vulnerability is due to insufficient validation of user-supplied input to the web-based management interface”.

Cisco Small Business RV Series Routers Web Filter Database Update Command Injection Vulnerability:

This vulnerability is tracked as (CVE-2022-20827) with the CVSS Base Score: 9.0 found in the web filter database update feature of Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers.

This could allow an unauthenticated, remote attacker to perform a command injection and execute commands on the underlying operating system with root privileges. It is due to insufficient input validation.

“An attacker could exploit this vulnerability by submitting crafted input to the web filter database update feature”, the advisory stated.

Cisco Small Business RV Series Routers Open Plug and Play Command Injection Vulnerability:

This flaw is tracked as (CVE-2022-20841) with the CVSS Base Score: 8.3 found in the Open Plug and Play (PnP) module of Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers.

The flaw could allow an attacker to inject and execute arbitrary commands on the underlying operating system. It is due to insufficient validation of user-supplied input. Upon successful exploitation, this could allow the attacker to execute arbitrary commands on the underlying Linux operating system.

Cisco says “An attacker must leverage a man-in-the-middle position or have an established foothold on a specific network device that is connected to the affected router”.

Cisco Released Patches to Address the Vulnerabilities

CVE-2022-20827 and CVE-2022-20841

CVE-2022-20842

Cisco has released patches for three vulnerabilities which are rated ‘Critical’ and ‘High’ in severity. Cisco recommends upgrading to an appropriate fixed software release and there are no workarounds that address these vulnerabilities.

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