Turning Network Free-Riders' Lives Upside Down

An anonymous reader writes "You discover that your neighbours are using your unsecured wireless network without your permission. Do you secure it? Or do you do something more fun? A few minutes with squid and iptables could greatly improve your neighbours' Web experience ..." Improve is a relative term, but this is certainly gentler than certain other approaches.

Comments

Goats

[ajiva]

I'm surprised the guy didn't send every link to goats.ex... He was being way too nice.

Re:Goats

[Roody Blashes]

If you don't secure a wireless connection that spills onto other people's property, why shouldn't they use it until told otherwise? You could argue that you're not really encroaching, but I guarantee you that's not true. There's another network near us that was too weak to always show in the list of nearby nets, but was just strong enough to cause intermittent signal pollution until one day I happened to move the router to get at something else, and noticed it next time I connected.

If you let your signal spill over onto other people's space, too bad.

In fact, I wouldn't be mad if someone were using my connection without my approval unless they were encroaching on my space to do it. In fact, I only secured it because of bandwidth concerns and the potential for other people to use it for illicit purposes.

Re:Goats

[trewornan]

I chose to leave my wireless network open so that if someone nearby needed a connection it would be available for them. If someone was to impose an unreasonable load on the network I might do something about it but so far (12 months) I've had about half a dozen people connect and download relatively small amounts of data - my guess is they were checking email. Why would I object to that? No . . . why would *you* object to that? The way I see it it's a chance to do something nice for other people, why not get yourself some good karma.

Re:Goats

[generic-man]

I've lived in two places where I set up my access point with no encryption. In both places, I've fired up iTunes to see someone else sharing music on my LAN. This didn't bother me until I read the name of the share: "(name)'s LimeWire Tunes."

I don't mind if people want to check their e-mail on my WAP. I do mind when they idle on file sharing services, using lots of bandwidth and exposing me to potential legal liability.

It's a shame that I have to protect my router somehow, especially because one of my devices (a Nintendo DS) doesn't support WPA at all.

Re:Goats

[Starker_Kull]

It shouldn't be too hard to set up some fixed IP addresses for your home machines, and let "guests" use a different IP range, for which you have implemented port blocking for all but 80, 25 and a few others for https and sending email, if you wish.

Re:Goats

[element-o.p.]

Unfortunately, not everyone is as kind (or patched/anti-virus'ed/etc.) as your neighbors are.

I spent three years as an abuse admin at an ISP, and spoke with a number of customers where the only likely culprit for an abuse complaint was someone "borrowing" their Wi-Fi connection (nmap is a wonderful tool for finding likely infections/file sharing clients). In almost all of these cases, securing the Wi-Fi access point made the problem go away.

It's possible that my customers were lying and that they just latched on to the Wi-Fi excuse to get me off their backs, but after three years, it (usually) wasn't too hard to tell when someone honestly had no clue and when they were covering up :)

So *that's* why I object to people using my Wi-Fi without permission.

It's not their fault...

[nick_davison]

How can you blame people for connecting to a wireless router with the ID "Free Porn"?

Granted, my neighbors didn't intentionally set their router up with that ID but they did leave it unsecured with the default password for the admin account. It was simply the neighborly thing to do to change their ID and resecure it with a new password (that, admittedly, they didn't know).

Can you imagine the tech support calls?

[Tackhead]

Substituting everything with Goatse or Tubgirl (Goatse was already done with airpwn at DEFCON 12) would be funny, but Joe Sixpack would call tech support, and they'd all shrug it off saying he'd been cracked with some sort of virus.

But can you imagine Joe Sixpack trying to explain to Pradeep that all the images in his web pages were being displayed upside-down (or better yet, blurry, or upside-down and blurry!), while all the text in the very same web pages was being displayed upside-right in crystal clarity?

Joe Sixpack probably doesn't know the differences between images and text. Pradeep would hear the word "upside down" or "blurry" and immediately think it was a hardware problem.

It'd probably take any of us half an hour to convince a second-tier tech that we weren't trolling him, never mind Joe Sixpack.

I'd give my left nut to hear the support calls on this. (Particularly as I'm pretty sure that those of you in tech support have no use for my left nut. :)

Re:Can you imagine the tech support calls?

[nizo]

I'd give my left nut to hear the support calls on this.

Maybe you can, if your neighbor is using your network connection to fullfill all his VOIP needs.

Understanding the Approach to this

[blantonl]

For those that are struggling to understand how the author of this article is accomplishing his approach, here is some further information.

The author obviously has a Linux server in his house, that is running DHCPD

To selectively send some clients to some locations, and others to the normal internet, he assigns an IP address on a different network to clients that don't have MAC Addresses that he knows about.

Forwarding on to sites of his choice is done by using IPTables, which is a utility that allows you to configure the packet filtering components of the Linux TCP/IP Stack. In this instance, the Linux box is just functioning as a firewall, and he is selectively sending requests from certain IP addresses to different hosts of his chosing.

Finally, the Up-side-down and blurry-image conversions is accomplished by sending page requests from those before-mentioned IP addresses to a proxy server, which in this case is Squid - and then allowing the proxy server to run a script which calls an ImageMagick command called mogrify which allows you to resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more.

And that folks, is the rest of the story.

Re:Understanding the Approach to this

[hab136]

$url = $1;
system("/usr/bin/wget", "-q", "-O","/space/WebPages/images/$pid-$count.jpg", "$url");

This line gives me chills. He's passing a completely unsanitized input (the bandwidth thief's URL) to a system() function.

At least he didn't concatenate everything so that system() would run the entire string as a shell command.. then simply adding a semicolon or pair of backticks to the url would cause the system to run any command the attacker liked, including deleting all files squid has access to and running a custom backdoor. There are a lot more local root-escalation flaws than remote.

Even without the shell character vulnerability, who knows what kind of failures you can induce out of wget given the right parameters. He should sanitize the URL before passing it out.

There's also the possibility of a vulnerability in mogrify, given the right corrupted image file to work on. Mogrify should be run in a separate user account that has no access to anything other than the input file.

Never trust your input, especially from an already-admitted evildoer.

Yes, I'm paranoid - I work in information security. :)

Re:You can't steal unprotected Wifi.

[realmolo]

Hey man,

I think that someone is redirecting your requests through a proxy server that randomly inserts the letter "o" into the word genius.

Moran.

Open Networks

[Elektroschock]

sorry, I am a supporter of open networks. I think the freifunk olsr-protocol approach of open wireless networks is best. We don't need internet providers and we don't need internet provider which leak our communication data to the governments and endanger the freedom of the net. The net should be a net and wireless technology is great for the creation of a real P2P internet.

I cannot support any action against people who use your network. It is against my understanding of hacker ethics. When you don't like it then close your network. But no childish games please.

I may even say that I find it unethical to exclude your neighbours from using your network but I respect your opinions. When your network is open it means: Be free to use it. Not: You can use it but I will fuck up or intercept your communication.

blurry-net

[Sloppy]

At first, I thought there were way too many screenshots. I mean, ok, we get it. But then at the bottom of the FA, it pays off. After the dumb kitten and upside-down stuff (where they know someone is fucking with them) we get to the treasure: blurry-net. That's subtle and I love it. The ideal prank for the proverbial Man In The Middle would be to do things to confuse the endpoints, not merely annoy them.

The next step is to spy on them and see what websites they visit, and then insert some fake content one day. For example, if they use it to read CNN, insert a casual story about a nuclear weapon getting used in the Middle-East or South Asia, or a story about the president of USA selecting a new vice-president due to the assassination last week ("What?! I didn't hear about that!"), or the CDC in Atlanta is investigating the recent rash of improbable claims about the dead returning to life to feast on the flesh of the living, etc. If they visit Slashdot, then the jig is probably up, but maybe it would be great to have a story where a security study found Windows98 to kick OpenBSD's ass and then a bunch of comments where everyone agrees that the findings pretty much match their own experience, along with complains about "how is this news for nerds?!"

Certainly one could be *far* more evil than this..

[Anonymous Coward]

Network freeloaders put themselves at risk... It would be trivial for someone to set up a "Free Internet" wireless AP and then run phishing attacks, sniff IM conversations, e-mail, etc. Considering how little the average internet user even pays attention to SSL, one could very easily imitate a bank, ebay, paypal, etc... One should certainly think twice before freeloading on someone's wireless network - and if you do, at least tunnel your connection securely (even socks5 over an SSH tunnel, etc)..

Re:Missing the point, I think

[squiggleslash]

No, it's not implied. As the law stands, it's illegal unless you get something more explicit in terms of permission. Yes, illegal. Yes, people have lost in court. No, not civil court, criminal.

(And it makes sense that no implied permission is given by simply having your router be unsecured, given "unsecured" is the default configuration of most off-the-shelf routers.)

It really isn't an issue in practice. If you want to use someone else's network, all you have to do is ask them. With 802.11, you're close enough to be able to do so. There's no reason not to ask, other than knowing that "no" is likely to be the answer. And I think that's why people tell themselves the myth that somehow they have implied permission simply because the "door" was left unlocked.

Hello, tech support?

[jpellino]

Upside down is cute, but blurry is just too fantastic.
You know they were on the horn to the vendor after punching every monitor control and several loud screaming matches and an expensive service call for a monitor that then worked just fine on the bench...
As a webmaster I can now say April 1 just got very far away...

Re:Missing the point, I think - absurd.

[4e617474]

What you are saying is that, unles I put a tarp up around my garden, everyone has a right to use it.

No, actually we're saying that if your garden pelts us with carrots and peas as we walk past on the public street, we're at liberty to catch them and consume them. Only if you place anti-vegetable-flight netting around your garden (or stop planting vegetables that lend themselves to comparison to an unsecured WAP) does it become incumbent upon us to behave as good citizens.

Hey! Analogies are fun! Somebody compare Internet privacy law to hunting and fishing licenses!