Worm exploits nasty Shellshock bug to commandeer network storage systems
"The attack targets a QNAP CGI script, /cgi-bin/authLogin.cgi, a well known vector for Shellshock on QNAP devices," Johannes B. Ullrich, dean of research at Sans, wrote. "This script is called during login, and reachable without authentication. The exploit is then used to launch a simple shell script that will download and execute a number of additional pieces of malware."
Infected systems are equipped with a secure shell (SSH) server and a new administrative user, giving the attackers a persistent backdoor to sneak back into the device at any time in the future, Ullrich said. The worm also patches the Shellshock vulnerability, presumably to prevent other attackers from taking over the compromised device. Infected devices also execute a script that makes them carry out a click-fraud scam against an advertising network. A variety of other scripts are also installed.