This site uses a malicious script that makes automatic login in some modem models and performs modifications of DNS:
http://www.cavokbrasil.com
This site is running a malicious script:
http://cavokbrasil.com/blog/cavokbrasil.js
This script modifies the Nameservers of the affected modems. The Nameservers are changed for these:
65.181.113.176
65.181.113.192
One of the affected modem models is the TP-Link TD-8810.