It seems like there is a high volume of malware (and little legitimate traffic) recently that's originating from the .cc domain. How would an enterprise assess whether the insecurity of an entire domain demands blocking traffic from said domain at the network perimeter?
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While it is possible that a network may receive a high volume of .cc domain malware and little legitimate traffic from that domain, security professionals may want to take a more in-depth look at the IP sources and not just assess the security of a DNS name.
DNS names can be configured to point to any IP address that could be within your company or, theoretically, in the Cocos Islands, an Australian territory for which .cc is the assigned top-level domain (TLD). Any IP could potentially be blocked on a network hosted at an ISP in the Cocos Islands, blocking malicious traffic will not be entirely effective. If an organization continues to get constant attacks from hosts with DNS names in the .cc namespace, contacting the upstream ISP or the domain registrar is the logical starting point, although this may also not be effective (some ISPs are known to be unresponsive to such requests). Enterprises may also contact CERT to report attacks. It should be noted that Google has dropped the .co.cc domain from its search index, which will prevent many users from getting infected, but this will not stop systems that are using .cc domain names from attacking enterprise networks.
Security experts have suggested dropping all .cn traffic via full domain blocking for similar reasons, but given the ease of obfuscating the source of an attack, ultimately blocking .cn or .cc DNS names will not stop attackers from attacking a network.
This was first published in May 2012