Netgear R6700v3 Unauthenticated LAN Admin Password Reset

Description

This module targets ZDI-20-704 (aka CVE-2020-10924), a buffer overflow vulnerability in the UPNP daemon (/usr/sbin/upnpd), on Netgear R6700v3 routers running firmware versions from V1.0.2.62 up to but not including V1.0.4.94, to reset the password for the 'admin' user back to its factory default of 'password'. Authentication is bypassed by using ZDI-20-703 (aka CVE-2020-10923), an authentication bypass that occurs when network adjacent computers send SOAPAction UPnP messages to a vulnerable Netgear R6700v3 router. Currently this module only supports exploiting Netgear R6700v3 routers running either the V1.0.0.4.82_10.0.57 or V1.0.0.4.84_10.0.58 firmware, however support for other firmware versions may be added in the future.

Once the password has been reset, attackers can use the exploit/linux/telnet/netgear_telnetenable module to send a special packet to port 23/udp of the router to enable a telnet server on port 23/tcp. The attacker can then log into this telnet server using the new password, and obtain a shell as the "root" user.

These last two steps have to be done manually, as the authors did not reverse the communication with the web interface. It should be noted that successful exploitation will result in the upnpd binary crashing on the target router. As the upnpd binary will not restart until the router is rebooted, this means that attackers can only exploit this vulnerability once per reboot of the router.

This vulnerability was discovered and exploited at Pwn2Own Tokyo 2019 by the Flashback team (Pedro Ribeiro + Radek Domanski).