Intelbras WRN240 devices do not require authentication to replace the firmware via a POST request to the incoming/Firmware.cfg URI.

XSS (persistent) on the Intelbras Wireless N 150Mbps router with firmware WRN 240 allows attackers to steal wireless credentials without being connected to the network, related to userRpm/popupSiteSurveyRpm.htm and userRpm/WlanSecurityRpm.htm. The attack vector is a crafted ESSID, as demonstrated by an "airbase-ng -e" command.