The Unmask Parasites blog discusses a technique attackers are using more and more often recently: modifying a compromised site's DNS settings to redirect various subdomains to different IPs that serve up malware
, often leaving site administrators none the wiser. Quoting:
"It is clear that hackers have figured out that subdomains of legitimate websites are an almost infinite source of free domain names for their attack sites. With access to DNS settings, they can create arbitrary subdomains that point to their own servers. Such subdomains can hardly be noticed by domain owners who rarely check their DNS records after the initial domain configuration. And they cost nothing to hackers. I wonder if using hijacked subdomains of legitimate websites is a new trend in malware distribution or just a temporarily solution that won't be widely adopted by cybercriminals in the long run (like dynamic DNS domains last September)."