Cybercriminals Building New, Stealthier Networks

ancientribe writes "Cybercriminals are adopting a new method of hiding and sustaining their malicious Websites and botnet infrastructures so they'll be harder to detect, called "fast-flux," according to an article in Dark Reading. Criminal organizations behind two infamous malware families — Warezov/Stration and Storm — in the past few months have separately moved their infrastructures to so-called fast-flux service networks. The article says bad guys like fast-flux not only because it keeps them up and running, but also because it's more efficient than traditional methods of infecting victims' machines." I'm not exactly sure why this is new/different than the more well known open relay proxy networks.

Block TCP Port 80

[quanticle (843097)]

What can be done about fast flux? ISPs and users should probe suspicious nodes and use intrusion detection systems; block TCP port 80 and UDP port 53; block access to mother ship and other controller machines when detected; "blackhole" DNS and BGP route-injection; and monitor DNS, the report says.

The bit about blocking TCP port 80 is troubling. I run a small web-site for learning purposes and to share info with family and friends. I don't especially like the possibility of having to ask or pay extra to have port 80 opened on my end.

Re:

[brunes69 (86786)]

So run it on port 8080 or something else. There is nothing magical about port 80 that you have to run a website on it.

Re:

[Sobrique (543255)]

I take it you mean except the IANA assigned port number?

How about outbound firewall and proxy configurations?

Re:Block TCP Port 80

[Otis2222222 (581406)]

That sounds great, I am sure it would be no problem whatsoever to tell your friends "My website is at dub-dub-dub dot mywebsite dot com, colon eighty eighty. And if you don't type the 'eighty eighty' you won't get there. Don't forget to type colon eighty eighty, grandma".

And what the other guy said about proxies is valid too. It's very common for outbound corporate firewalls to block non-port-80 traffic for web browsing.

Re:Block TCP Port 80

[veganboyjosh (896761)]

Mr. Potatahead! Mr. PotataHEAD! Getting around port blocks is not secret!

Re:

[InsaneMosquito (1067380)]

Charter.net blocks port 80. It was PITA to figure out why I couldn't connect to my webserver from outside the Charter network. While inside their network I could just fine. Once I figured it out though, its was as simple as moving the webserver to a different port. I picked 443 because they allow secure websites. From there I just set up a little domain forwarding/cloaking so that end users never see they are connected to 443 and don't use SSL - its not needed for the type of site I have hosted.

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[CastrTroy (595695)]

I've never got why people want to run a webserver on their home computer over a cheap cable/dsl connection. I tried it for a while but between the cost of the extra computer, the cost of the extra electricity, the trouble of setting up all the server software on my own, and the trouble of dealing with changing IPs, and all the other wonderful cable ISP network oddities, I found it easier to just pay a cheap monthly fee for a shared hosting account. It's nice to run a home server for some things, but if it

Re:Block TCP Port 80

[by Anonymous Coward]

With power comes responsibility. If you want unfettered internet access, it's your responsibility to make sure that your participation in this network doesn't cause problems for others. Since most residential internet users have neither the ability nor the intention to shoulder that responsibility, their upstream provider has to find ways to protect other internet users from his customers, because if he doesn't, he will ultimately have to pay for the damage that they do (higher traffic costs, less favorable peering agreements, blacklisting, etc.)

The net has grown very fast and so far we've shirked the responsibility issue: Customer's complain about spam and when the spammer's provider says it's not their responsibility, they're called a safe-haven for spammers. On the other hand, when customers get cut off because their computers are scanning and infecting other machines, they complain that it's not their fault and how are they supposed to keep their system clean without a full time admin and it's none of the ISPs business as long as the internet access bills are paid.

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[matt328 (916281)]

I believe they're talking about blocking inbound traffic on port 80. My old ISP, Adelphia blocked inbound traffic on port 80 and my internet connection was very much functional.

Re:Block TCP Port 80

[utopianfiat (774016)]

This is what Slashdot has become.
Two years ago there would have been a frosty piss and a two-page discussion on how this douchebag OP was wrong to use the word "cybercriminals" (or cyberfoo for that matter), and how his article reads like a page out of the script to this flaming piece of shit. [imdb.com] Where did we go? Since when did Slashdot become Eternal September?
That's right point-bearing masses, mod me flamebait because nobody else has the balls to stand up to this kind of terrible quality news. FFS look at the damn article! It says nothing! It literally states something that was true ten years ago when the botnet was invented! News for NERDS? more like News for NEWBS.
Christ alfuckingmighty.

So, in the end

[vivaoporto (1064484)]

These criminals are giving a "smarter" * use for the enormous potential that these hundred thousands of homogeneous (or similar enough) connected machines have than most companies out there does. It is time for 1) Microsoft and its users get their act straight and work on better security for they machines and 2) someone to realize the incredible potential of all this "dark" bandwidth and processing power and give it a good use. Criminals are showing it is possible, all it need is some legitimate application

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[mrbluze (1034940)]

These criminals are giving a "smarter" * use for the enormous potential that these hundred thousands of homogeneous (or similar enough) connected machines have than most companies out there does. It is time for 1) Microsoft and its users get their act straight and work on better security for they machines and 2) someone to realize the incredible potential of all this "dark" bandwidth and processing power and give it a good use. Criminals are showing it is possible, all it need is some legitimate application.

Yes, it's time the Empire of Nastiness started to use its powers for good instead of evil.

" why is this new/different"

[tomhudson (43916)]

"I'm not exactly sure why this is new/different than the more well known open relay proxy networks."

... which just goes to show that even spammers can fall victim to their own marketing:

Tired of your botnets getting killed off? Use fast-flux. See a 30% increase in only 2 days. She'll love you for it!.

What's special about port 80?

[Control Group (105494)]

I am not a networking guru (IANANG, copyright 2007, me, all rights reserved), so I'd appreciate somebody setting me straight on this if necessary.

But I don't really see how blocking port 80 would be an effective way to fight this sort of thing. There's nothing special about port 80 aside from it being the default http port. Unless the victims are typing the URL into their address bar, I don't see any reason the mother ship couldn't have bots listen on another port. I mean, the machine is already owned, so it's not like opening up port 43783 is difficult. And I can't help believing that most - if not all - people going to these sites are clicking links, not typing addresses.

So you close off port 80, and anyone running a legit (well, probably not, given the TOS of most ISPs, but at least not a malicious) web server out of their house/apartment/dorm room can no longer easily direct people to it. Meanwhile, the malicious sites are slowed down by the amount of time it takes some jackass to change one constant in one piece of code.

Unless, of course, there's some other factor I'm unaware of making it more difficult to reach an http host over something other than port 80.

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[timeOday (582209)]

I'm not saying it's a good idea. But the intruders do need some way to access the machine at will. If they leave a port listening, the OS knows and can tell the user (netstat) or firewall it unless the OS is also compromised. If the OS is compromised, it still wouldn't be long until somebody figures it out and massive blocking on that port could occur by ISPs (as is being suggested). The bot could poll some website to update itself, such as triggering a switch listening on a new port, but that would be

Re:What's special about port 80?

[Control Group (105494)]

*shrug*

Randomly select a different port each time you connect to the zombie. If you're really worried about users running netstat to check their open ports (and I suspect that zombied machines are more often owned by people who don't even know the CLI exists, much less who generally run network diagnostic tools via the CLI than not - and by a wide margin), then have it only open the port for ten minutes every hour. Windows, by default, updates its clock to NIST weekly, so you can be reasonably sure that your zombies are synced enough for that to work. Round-robin assign the ten minute window to the zombies (xx:00 - xx:09, xx:01 - xx:10, xx:02 - xx:11, etc). During that window, you use the zombie to host content, and you can push a listen port update. At any given time, most of your zombies are running on the same port (they have to be, or your victims can't connect to your content), but blocking that port will only be effective for however long you determine. How fast can ISPs identify a rogue port and block it?

If my experience with spam is any indication, the linked sites go down almost as fast as the spam comes in, but that's (apparently) not a problem for the spammers. So you rotate ports every two, three days.

And this is just the scheme I've come up with off the top of my head in less than a minute.

Come to think of it, you're already executing arbitrary code on the zombied machine. Have them determine when they can listen on their assigned port, with a minimum frequency and duration set, with a bias towards times the user isn't at the console. When the window opens, step one is to notify the mother ship that this machine is active.

There are probably holes in this scheme, but I don't see the problem as being intractable. I do see any effort to just block port 80 as being naive (at best). I don't think ISPs can respond fast enough to block a new port every couple days, but perhaps I'm wrong about that.

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[GnuDiff (705847)]

AFAI have looked, port 80 is the one that is least likely to be stopped by firewalls.

There are a number of small (and I mean tiny - think 100 clients max) ISPs around my city alone, whose networking expertise is close to nil. They go with default settings of the equipment they get. So even if they put up a firewall of sorts to protect their clients, it is left at default settings.

The fact is there are not only tons of users out there without a clue, but a nice bunch of ISPs as well and sloppy network admins

Re:What's special about port 80?

[orclevegam (940336)]

The blocking of port 80 they suggest really isn't about stopping the fast flux network, but it's an attempt to make it harder (marginally) to use the systems on that network for phishing attacks. As I understand it one of the uses these networks are being put to is to duplicate a phishing site on a couple hundred zombie systems, then rotate a single phishing URL through all of them making it harder to bring down the phishing site because you'd have to take down every one of the zombies, or find some way of nuking the DNS entry (which apparently the registrars are hesitant to do, even though some recent events seem to show that they'll do it quite happily if a big enough company or corporation asks them to). Personally I think blocking port 80 is a dumb idea and barely constitutes a speed bump for the kinds of people that run these things, but hey, that's never stopped a company from adopting a stupid idea, or marginal positive value and substantial negative (to the customer, if it hurts their bottom line forget it).

Know Your Enemy paper on Fast Flux just out

[by Anonymous Coward]

Has a lot more detail: http://www.honeynet.org/papers/ff/fast-flux.html [honeynet.org]

Fast-flux vulnerability

[Todd Knarr (15451)]

Fast-flux takes advantage of the ability to set extremely low time-to-lives on DNS resource records. The shorter the TTL, the faster changes propagate out through the DNS cache network. This suggests a way of neutering fast-flux: implement a minimum TTL in DNS servers. Since most people depend on their ISP's DNS servers rather than going directly to the roots, this would effectively prevent the fast-flux record changes from propagating as fast as they need to to be effective. If, for example, an ISP put a 30-minute minimum TTL in place, then the A record for a given name would remain fixed for 30 minutes (modulo cache being filled and the record being forced out) regardless of what the fast-flux network did. And since the DNS servers enforcing the minimum typically aren't under the control of either the botnet or the infected machines, there's nothing the botnet operators can do about the situation. As a side-effect, this also cuts the load on the DNS network caused by PHBs who order 60-second TTLs on their records "so customers won't be inconvenience when we change our IP addresses".

Two glitches with the idea:

1. Changes to the NS records for a domain are also slowed down. When changing your NS records you need to make the changes but leave the old servers running in parallel long enough for the changes to trickle out to everybody.
2. Load balancing via round-robin DNS would be broken unless the caching servers also do rotation of the cached records in responses. I think BIND already does that.

Fast-flux networks aren't proxies

[jbsoles (1129855)]

As the subject implies, fast-flux networks are not proxies. They HAVE proxies. The basic difference is that a proxy redirects incoming and outgoing traffic through a server or router some where else, thus "spoofing" your IP address. Fast-flux networks certainly use proxies, but there's one big difference; fast-flux networks allow you to host content this way. To host your own website (short of technical mastery) you used to need a static IP address that runs directly to one or more servers, making it very easy to catch you if you use a domain name for illegal purposes and even easier to shut you down. Fast-flux networks allow you to use many IP addresses to host content from one central server or set of servers. The IP's on the front end are disposable and more can be generated quickly. It also provides the web site administrator a proxy level to protect his identity while hosting just like the one Tor proxy provides me while surfing. In other words, the difference between fast-flux networks and proxies is that fast-flux networks can be used to host from one computer to many different IP addresses, in part by using proxies. A proxy just doesn't let you do that. Thanks for reading a rather long post. I'm a student and a paper on fast-flux networks just happened to be distributed where I do research for the summer:)

JUST SAY IT! "Home PCs" = Windows OS

[Jerry (6400)]

ALL of these zombies are computers running a Windows OS.

There. I've said it. Why hide the truth?

Are journalist thinking "everyone knows it is Windows that is so vulnerable to mere emails, so there's no use in embarrassing Microsoft"? I don't think so... any more than they "just happened" to get Ferrari laptops for writing good articles about VISTA.

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[Hoi Polloi (522990)]

Windows=Kiddie Porn? Sounds like those ads that claim pot=terrorism. A bit of a stretch.

Re:So Windows is used to host illegal materials...

[CaffeineAddict2001 (518485)]

Them: So you don't like Children? Why not?
You: Because criminals use vulnerabilities in children to conduct their illicit affairs.

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[Mathinker (909784)]

> even most of the "white hat" hackers are "cybercriminals"

Checking http://en.wikipedia.org/wiki/Hacker_definition_con troversy [wikipedia.org] gives Linus Torvalds as an example of a hacker of the "other definition"... in what way is he a cybercriminal?

I hope whoever modded your pitifully binary views on the meaning of language terms as Insightful gets his due via meta-moderation... It is true that the new meaning of this term seems to be the more used one now, in what way does that make the old meaning obsolete, or th