Cisco Small Business RV016, RV042, RV042G, RV082 , RV320, and RV325 Routers Cross-Site Scripting Vulnerabilities

Vulnerability

The web-based management interface of Cisco Small Business RV016, RV042, RV042G, RV082, RV320, and RV325 routers contains multiple stored cross-site scripting (XSS) vulnerabilities [1]. These arise from insufficient input validation by the interface. An unauthenticated, remote attacker can exploit these by sending crafted HTTP requests to an affected device, then convincing a user to visit a specially crafted page that includes malicious payloads [1]. No software updates have been released by Cisco [1].

Exploitation

An attacker must be able to send crafted HTTP requests to the affected router's web management interface (no authentication required) [1]. The attacker then needs to persuade a user of the interface (e.g., an administrator) to access a specific web page containing the malicious payload — this is typically achieved through social engineering or by embedding the link in a phishing email [1]. The attack chain does not require prior access to the device. The vulnerability exists in the web-based management interface, so exploitation can occur over both LAN and WAN if remote management is enabled [1].

Impact

Successful exploitation allows the attacker to execute arbitrary script code in the context of the affected web management interface, or to access sensitive browser-based information (e.g., cookies, session tokens) of the legitimate user [1]. This could lead to takeover of the administrator session or leakage of configuration data. The scope of compromise is limited to the browser session of the interacting user; however, given that the victim is likely an administrator, the attacker could potentially perform actions within the session's privileges on the router [1].

Mitigation

Cisco has not released software updates that address these vulnerabilities, and they have stated that no workarounds exist [1]. For RV320 and RV325 routers, Cisco recommends disabling remote management via the web interface (Firewall > General > uncheck Remote Management) [1]. For RV016, RV042, RV042G, and RV082 routers, in addition to disabling remote management, administrators should block access to ports 443 and 60443 using access rules (Firewall > Access Rules) [1]. These mitigations prevent external attackers from reaching the vulnerable interface; however, internal LAN-based attacks are still possible [1].