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Malware on Hijacked Subdomains, a New Trend? 24

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)."
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Malware on Hijacked Subdomains, a New Trend?

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  • by Anonymous Coward on Saturday May 22, 2010 @12:24PM (#32306148)

    This is also done with 404 Error pages. They change it to redirect to their spam, and then point people at what looks like a legitimate URL. Then they get redirected to the spam and are none the wiser. could redirect anywhere.

    • by Anonymous Coward on Saturday May 22, 2010 @12:32PM (#32306226)

      Agreed 404, 301, 302. Anything that you can drop a .htaccess file into an account.

      Ideally, web servers (not just DNS) have a lot of holes, allowing NS access to the user isn't the problem like the TFA implies. Because most automation software doesn't allow for too much sub domain specific flexibility, most times you still need to be in root to redirect at a dns level.

      The exception is say parking (godaddy etc) or zoneedit but usually once its hosted it's pretty much in the hands of the admin to delegate externally.

    • by DeadPixels ( 1391907 ) on Saturday May 22, 2010 @01:12PM (#32306486)
      While I've yet to personally see any subdomain hijacking, I have come across 404 pages that have been turned into drive-by-downloads. Otherwise legitimate sites have all of these extra pages created ( that actually just point to malware. While most of them are still fairly easy to pick out because the domain is entirely unrelated to the search term, it's still dangerous and could easily catch many unobservant users.
    • Re: (Score:3, Interesting)

      So can these hacks be used to get around "NoScript"? I currently have it set to:

      - Temporarily allow top-level sites by defualt
      --- Base 2nd level Domains (

      • In general, any security tool configured to trust a subdomain of a trusted domain would be vulnerable to this attack.

        See also "Trusted Sites" in IE.

      • In this attack, the hacked sites redirect to subdomains of third party sites. E.g. redirects to, so most NoScript settings should be safe.
  • Wildcard SSL (Score:3, Interesting)

    by oztiks ( 921504 ) on Saturday May 22, 2010 @12:25PM (#32306164)

    Since a lot of hosting automation software (cPanel) sets up an a name for @ giving the power singularly to apache also lends it self to have the ability to mask it as being secure.

    It isnt a nameserver its moreover a webserver one.

  • by davidwr ( 791652 ) on Saturday May 22, 2010 @12:28PM (#32306188) Homepage Journal

    "who rarely check their DNS records"

    And thereinlies both the problem and the solution.

  • by Anonymous Coward on Saturday May 22, 2010 @12:44PM (#32306312)

    Yes, checking the DNS records will help identify the sites that have been modified, however it will also identify the hackers servers IP numbers. With that thread, you can start to unravel the illicit infrastructure, and counteract it.

    • Re: (Score:2, Interesting)

      At least in the example given, it would seem pretty feasible to do this at the GoDaddy site itself, where all the A records are centralized. How many businesses registered with GoDaddy have subdomains in different class A or even class B networks?
  • That explains :-)

  • . . . is that I have always set DNS addresses manually. Back before the days of DHCP, I got to know the two primary DNS addresses for Level3 (now Verizon), & Since I have an easier time remembering numbers than names, they stuck. I use them even though they are not my ISPs, which makes DN look-ups a little slow.

    There are a number of well known DNS exploits, especially with DNSSEC ( being a late comer to the Internet and not widely implemented beyond top level d
  • by ma1wrbu5tr ( 1066262 ) on Saturday May 22, 2010 @02:40PM (#32307292) Journal
    I can verify that this trend has been building for months. It only seems to be getting worse. We've logged literally hundreds of compromised sites ranging from the very high traffic to the very obscure. This is one case where even vigilant users are undermined by the lack of security awareness of the site admins.
  • "Malware on Hijacked Submarines, a New Trend?"

    Talk about a double-take! Would have made for an interesting story, though :)

  • > 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).

    Well, if my co-workers' research with URL-shortener links is any indication, you can certainly train people in a Pavlovian manner to avoid following links to unknown content.

Always leave room to add an explanation if it doesn't work out.