Symantec’s telemetry has shown over 12 million Intrusion Prevention Signature (IPS) hits on sub domains of the ‘CO.CC’ domain in the last six months. Anyone somewhat familiar with the top-level domain-naming hierarchy might be lead to believe that CO.CC is actually an official second-level domain similar to CO.UK; this, however, is not the case. .CC is the Internet country code top-level domain (ccTLD) for Cocos (Keeling) Islands, an Australian territory. "CO.CC" is not an official hierarchy; it is a domain owned by a company that offers free sub domains and other services such as URL forwarding. The terms and conditions for use of the ‘CO.CC’ Web site can be found here.
The CO.CC domain itself is legitimate and has registered over eight million legitimate website URLs on its sub domains. However, wherever a free service exists, it is susceptible to being abused by malware distributors. A malware distributor can register several free sub domains and use the URL forwarding service to point them all to one domain hosting a crimeware exploit pack. This way an attacker can stage their attack through redirection and try to mask the final URL destination hosting the exploit pack. This in turn makes it more difficult for the black listing of malicious URLs. In our analysis, we have seen numerous exploit packs such as Black hole, Fragus, Phoenix, Crimepack, K0de, and Eleonore being associated to CO.CC sub domains.
This may not sound very innovative to some readers, as in the past we have seen other free services, such as free dynamic DNS sites, being abused by malware distributors. Attacks such as Hydraq (Aurora) highlighted the use of dynamic DNS by attackers and has lead to numerous companies blocking the use of dynamic DNS sites on their network. The use of free services on sites, such as the one highlighted in this blog, has given attackers another avenue for performing their attacks.
In our research, we have also identified variants of the following threats to be communicating with CO.CC sub domains.
Threats seen using CO.CC sub domains
As always, Symantec recommends that you keep your definitions up to date to ensure protection against threats mentioned in this blog.