Vulnerability Note VU#582384

CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection'), CWE-306: Missing Authentication for Critical Function, and CWE-352: Cross-Site Request Forgery (CSRF)

R6250, R6400, R6700, R6900, R7000, R7100LG, R7300, R7900, R8000, D6220, and D6400 contain an unauthenticated command injection vulnerability that may be executed directly or via cross-domain requests. Known affected firmware versions include Netgear R7000 version 1.0.7.2_1.1.93, R6400 version 1.0.1.12_1.0.11, and R8000 version 1.0.3.4_1.1.2. Earlier versions may also be affected. The command injection vulnerability has been assigned CVE-2016-6277.

By convincing a user to visit a specially crafted web site, a remote, unauthenticated attacker may execute arbitrary commands with root privileges on affected routers. An unauthenticated, LAN-based attacker may do the same by issuing a direct request, e.g. by visiting:

http://<router_IP>/cgi-bin/;COMMAND

An exploit demonstrating these vulnerabilities has been publicly disclosed.

Netgear's advisory indicates that the R6250, R6400, R6700, R6900, R7000, R7100LG, R7300DST, R7900, R8000, D6220, and D6400 are vulnerable, though affected firmware versions are not enumerated. The vendor has indicated in their advisory that all listed models now have firmware updates available.

By convincing a user to visit a specially crafted web site, a remote unauthenticated attacker may execute arbitrary commands with root privileges on affected routers.

Apply an update

Netgear has released firmware updates for the affected models specified in their advisory. Users are strongly encouraged to update as soon as possible. For users unable or unwilling to apply a firmware fix, we recommend the following workarounds.

Disable web server

The very vulnerabilities that exist on affected routers may be used to temporarily disable the vulnerable web server until the device is restarted:
http://<router_IP>/cgi-bin/;killall$IFS'httpd'
Note that after performing this step, your router's web administration not be available until the device is restarted. Please see Bas' Blog for more details.

Do not enable remote administration

Enabling remote administration allows affected routers to be exploited via direct requests from the WAN. As such, users are strongly advised to leave remote administration disabled, or disable it if is has been enabled previously.