Entries Tagged "Wi-Fi"

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Terrorists Using Open Wireless Networks

Remember when I said that I keep my home wireless network open? Here’s a reason not to listen to me:

When Indian police investigating bomb blasts which killed 42 people traced an email claiming responsibility to a Mumbai apartment, they ordered an immediate raid.

But at the address, rather than seizing militants from the Islamist group which said it carried out the attack, they found a group of puzzled American expats.

In a cautionary tale for those still lax with their wireless internet security, police believe the email about the explosions on Saturday in the west Indian city of Ahmedabad was sent after someone hijacked the network belonging to one of the Americans, 48-year-old Kenneth Haywood.

Of course, the terrorists could have sent the e-mail from anywhere. But life is easier if the police don’t raid your apartment.

EDITED TO ADD (8/1): My wireless network is still open. But, honestly, the terrorists are more likely to use the open network at the coffee shop up the street and around the corner.

Posted on August 1, 2008 at 6:46 AMView Comments

My Open Wireless Network

Whenever I talk or write about my own security setup, the one thing that surprises people — and attracts the most criticism — is the fact that I run an open wireless network at home. There’s no password. There’s no encryption. Anyone with wireless capability who can see my network can use it to access the internet.

To me, it’s basic politeness. Providing internet access to guests is kind of like providing heat and electricity, or a hot cup of tea. But to some observers, it’s both wrong and dangerous.

I’m told that uninvited strangers may sit in their cars in front of my house, and use my network to send spam, eavesdrop on my passwords, and upload and download everything from pirated movies to child pornography. As a result, I risk all sorts of bad things happening to me, from seeing my IP address blacklisted to having the police crash through my door.

While this is technically true, I don’t think it’s much of a risk. I can count five open wireless networks in coffee shops within a mile of my house, and any potential spammer is far more likely to sit in a warm room with a cup of coffee and a scone than in a cold car outside my house. And yes, if someone did commit a crime using my network the police might visit, but what better defense is there than the fact that I have an open wireless network? If I enabled wireless security on my network and someone hacked it, I would have a far harder time proving my innocence.

This is not to say that the new wireless security protocol, WPA, isn’t very good. It is. But there are going to be security flaws in it; there always are.

I spoke to several lawyers about this, and in their lawyerly way they outlined several other risks with leaving your network open.

While none thought you could be successfully prosecuted just because someone else used your network to commit a crime, any investigation could be time-consuming and expensive. You might have your computer equipment seized, and if you have any contraband of your own on your machine, it could be a delicate situation. Also, prosecutors aren’t always the most technically savvy bunch, and you might end up being charged despite your innocence. The lawyers I spoke with say most defense attorneys will advise you to reach a plea agreement rather than risk going to trial on child-pornography charges.

In a less far-fetched scenario, the Recording Industry Association of America is known to sue copyright infringers based on nothing more than an IP address. The accuser’s chance of winning is higher than in a criminal case, because in civil litigation the burden of proof is lower. And again, lawyers argue that even if you win it’s not worth the risk or expense, and that you should settle and pay a few thousand dollars.

I remain unconvinced of this threat, though. The RIAA has conducted about 26,000 lawsuits, and there are more than 15 million music downloaders. Mark Mulligan of Jupiter Research said it best: “If you’re a file sharer, you know that the likelihood of you being caught is very similar to that of being hit by an asteroid.”

I’m also unmoved by those who say I’m putting my own data at risk, because hackers might park in front of my house, log on to my open network and eavesdrop on my internet traffic or break into my computers. This is true, but my computers are much more at risk when I use them on wireless networks in airports, coffee shops and other public places. If I configure my computer to be secure regardless of the network it’s on, then it simply doesn’t matter. And if my computer isn’t secure on a public network, securing my own network isn’t going to reduce my risk very much.

Yes, computer security is hard. But if your computers leave your house, you have to solve it anyway. And any solution will apply to your desktop machines as well.

Finally, critics say someone might steal bandwidth from me. Despite isolated court rulings that this is illegal, my feeling is that they’re welcome to it. I really don’t mind if neighbors use my wireless network when they need it, and I’ve heard several stories of people who have been rescued from connectivity emergencies by open wireless networks in the neighborhood.

Similarly, I appreciate an open network when I am otherwise without bandwidth. If someone were using my network to the point that it affected my own traffic or if some neighbor kid was dinking around, I might want to do something about it; but as long as we’re all polite, why should this concern me? Pay it forward, I say.

Certainly this does concern ISPs. Running an open wireless network will often violate your terms of service. But despite the occasional cease-and-desist letter and providers getting pissy at people who exceed some secret bandwidth limit, this isn’t a big risk either. The worst that will happen to you is that you’ll have to find a new ISP.

A company called Fon has an interesting approach to this problem. Fon wireless access points have two wireless networks: a secure one for you, and an open one for everyone else. You can configure your open network in either “Bill” or “Linus” mode: In the former, people pay you to use your network, and you have to pay to use any other Fon wireless network. In Linus mode, anyone can use your network, and you can use any other Fon wireless network for free. It’s a really clever idea.

Security is always a trade-off. I know people who rarely lock their front door, who drive in the rain (and, while using a cell phone) and who talk to strangers. In my opinion, securing my wireless network isn’t worth it. And I appreciate everyone else who keeps an open wireless network, including all the coffee shops, bars and libraries I have visited in the past, the Dayton International Airport where I started writing this and the Four Points Sheraton where I finished. You all make the world a better place.

This essay originally appeared on Wired.com, and has since generated a lot of controversy. There’s a Slashdot thread. And here are three opposing essays and three supporting essays. Presumably there will be a lot of back and forth in the comments section here as well.

EDITED TO ADD (1/15): There has been lots more commentary.

EDITED TO ADD (1/16): Even more commentary. And still more.

EDITED TO ADD (1/17): Two more.

EDITED TO ADD (1/18): Another. In the beginning, comments agreeing with me and disagreeing with me were about tied. By now, those that disagree with me are firmly in the lead.

Posted on January 15, 2008 at 3:33 AMView Comments

Breaking WEP in Under a Minute

WEP (Wired Equivalent Privacy) was the protocol used to secure wireless networks. It’s known to be insecure and has been replaced by Wi-Fi Protected Access, but it’s still in use.

This paper, “Breaking 104 bit WEP in less than 60 seconds,” is the best attack against WEP to date:


We demonstrate an active attack on the WEP protocol that is able to recover a 104-bit WEP key using less than 40.000 frames with a success probability of 50%. In order to succeed in 95% of all cases, 85.000 packets are needed. The IV of these packets can be randomly chosen. This is an improvement in the number of required frames by more than an order of magnitude over the best known key-recovery attacks for WEP. On a IEEE 802.11g network, the number of frames required can be obtained by re-injection in less than a minute. The required computational effort is approximately 2^20 RC4 key setups, which on current desktop and laptop CPUs in negligible.

Posted on April 4, 2007 at 12:46 PMView Comments

Drive-By Pharming

Sid Stamm, Zulfikar Ramzan, and Markus Jakobsson have developed a clever, and potentially devastating, attack against home routers.

First, the attacker creates a web page containing a simple piece of malicious JavaScript code. When the page is viewed, the code makes a login attempt into the user’s home broadband router, and then attempts to change its DNS server settings to point to an attacker-controlled DNS server. Once the user’s machine receives the updated DNS settings from the router (after the machine is rebooted) future DNS requests are made to and resolved by the attacker’s DNS server.

And then the attacker basically owns the victim’s web connection.

The main condition for the attack to be successful is that the attacker can guess the router password. This is surprisingly easy, since home routers come with a default password that is uniform and often never changed.

They’ve written proof of concept code that can successfully carry out the steps of the attack on Linksys, D-Link, and NETGEAR home routers. If users change their home broadband router passwords to something difficult to guess, they are safe from this attack.

Additional details (as well as a nifty flash animation illustrating it) can be found here. There’s also a paper on the attack. And there’s a Slashdot thread.

Cisco says that 77 of its routers are vulnerable.

Note that the attack does not require the user to download any malicious software; simply viewing a web page with the malicious JavaScript code is enough.

Posted on February 22, 2007 at 12:40 PMView Comments

Wi-Fi Eavesdropping

New York Times blog post on how easy it is to eavesdrop on an open Wi-Fi session:

Turns out there was absolutely nothing to it. John sat a few feet away with his PowerBook; I fired up my Fujitsu laptop and began doing some e-mail and Web surfing.

That’s all it took. He turned his laptop around to reveal all of this:

* Every copy of every e-mail message I sent *and* received.

* A list of the Web sites I visited.

* Even, incredibly, the graphics that had appeared on the Web sites I had visited.

None of this took any particular effort, hacker skill or fancy software. Anyone could do it. You could do it.

Nice to see this getting some popular attention.

Posted on January 8, 2007 at 6:20 AMView Comments

Securing Wireless Networks with Stickers

Does anyone think this California almost-law (it’s awaiting the governor’s signature) will do any good at all?

From 1 October 2007, manufacturers must place warning labels on all equipment capable of receiving Wi-Fi signals, according to the new state law. These can take the form of box stickers, special notification in setup software, notification during the router setup, or through automatic securing of the connection. One warning sticker must be positioned so that it must be removed by a consumer before the product can be used.

Posted on September 5, 2006 at 1:56 PMView Comments

WiFi Driver Attack

In this attack, you can seize control of someone’s computer using his WiFi interface, even if he’s not connected to a network.

The two researchers used an open-source 802.11 hacking tool called LORCON (Loss of Radio Connectivity) to throw an extremely large number of wireless packets at different wireless cards. Hackers use this technique, called fuzzing, to see if they can cause programs to fail, or perhaps even run unauthorized software when they are bombarded with unexpected data.

Using tools like LORCON, Maynor and Ellch were able to discover many examples of wireless device driver flaws, including one that allowed them to take over a laptop by exploiting a bug in an 802.11 wireless driver. They also examined other networking technologies including Bluetooth, Ev-Do (EVolution-Data Only), and HSDPA (High Speed Downlink Packet Access).

The two researchers declined to disclose the specific details of their attack before the August 2 presentation, but they described it in dramatic terms.

“This would be the digital equivalent of a drive-by shooting,” said Maynor. An attacker could exploit this flaw by simply sitting in a public space and waiting for the right type of machine to come into range.

The victim would not even need to connect to a network for the attack to work.

No details yet. The researchers are presenting their results at BlackHat on August 2.

Posted on July 6, 2006 at 1:52 PMView Comments

Schneier Asks to Be Hacked

Maybe I shouldn’t have said this:

“I have a completely open Wi-Fi network,” Schneier told ZDNet UK. “Firstly, I don’t care if my neighbors are using my network. Secondly, I’ve protected my computers. Thirdly, it’s polite. When people come over they can use it.”

For the record, I have an ultra-secure wireless network that automatically reports all hacking attempts to unsavory men with bitey dogs.

Posted on June 28, 2006 at 1:23 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.