How I cracked my neighbor's WiFi password without breaking a sweat

http://arstechnica.com/security/2012/08/wireless-password-easily-cracked/

by laxk • 14 years ago

240 141 14 years ago

rel• 14 years ago

You know, at the cost of $2,500 per year, (although I can't actually find where to purchase the software) you'd probably be better to just YouTube some kid's backtrack tutorial.

jetti• 14 years ago

Or get better at social engineering.

sil3ntmac2• 14 years ago

What software are you talking about? CloudCracker?

relix• 14 years ago

Read the article, or view it and press CTRL-F and type $2,500.

brown9-22• 14 years ago

Using the Silica wireless hacking tool sold by penetration-testing software provider Immunity for $2,500 a year, I had no trouble capturing a handshake established between a Netgear WGR617 wireless router and my MacBook Pro.

joshuahedlund• 14 years ago

> To his chagrin, it took CloudCracker just 89 minutes to crack the 10-character, all-numerical password he used...

> Remarkably, neither CloudCracker nor 12 hours of heavy-duty crunching by Hashcat were able to crack the passphrase. The secret: a lower-case letter, followed two numbers, followed by five more lower-case letters

So an all-number password was easily cracked with this method, but a shorter password with letters was untouchable?

Edit: I get that 10^10 is less than 36^8. I was more wondering how the cracker assumes, without knowing already if it's all-numeric or not, that it should try longer numerics before shorter alphanumerics and when it decides to give up on the numbers. I guess it's just known to be more likely for a good number of characters.

spicyj• 14 years ago

Surprising considering that the latter has less than 2 bits more entropy.

peterwwillis2• 14 years ago

All-number passwords are default on several ISPs so they're much more likely to succeed than a full keyspace search.

ajross• 14 years ago

By my math, a 10 byte sequence of decimal numbers has 33.2 bits of entropy, while a 8 byte sequence of lower case numerals and decimals has 41.3 bits. That's almost 300x as hard to crack.

There's also the issue of pattern heuristics. Number-only passwords seem like they'd be common, and thus a reasonable pattern to try out to ~35 bits or so (something that corresponds roughtly to "can be tried in a perceptively short time"), but it's not as clear that there's a significant fraction of passwords in the wild that use alphanumerics but no capitals. So they wouldn't try the passwords from the 36-character alphabet, more likely using a slower heuristic like things where the leading alpha character might be capital, or there might be punctuation between "words", etc...

rheide• 14 years ago

Most likely all the numbers up to 10 digits long were in the dictionary.

tl;dr of this article: don't use stupid passwords.

Edit: the article mentions it was a phone number, so that narrows it down a lot.

patdennis• 14 years ago

I'm assuming the ten character all numerical password was a phone number. Phone numbers have discernable patterns, like area codes.

mturmon• 14 years ago

Yes. The exchange (middle three for US numbers) also has patterns. More on the allowed codes is here:

http://en.wikipedia.org/wiki/North_American_Numbering_Plan

although, in practice, many of the allowed codes are not occupied. For instance, no exchange around LA would be 213, and no exchange near SF would be 415.

drzaiusapelord• 14 years ago

Look at it this way. Lets say I give you 5 characters to create a password. If you use all numbers then each value can be anywhere between 0 to 9. That's only 10 values! So that's 10 to the power of 5. That's only 100,000 permutations.

With letters, assuming standard English, you get 26 per value. Or 52 when we include case. That's a big difference. So lets say I only give you 4 lowercase characters. That's 4 to the power of 26. 456k permutations. So almost 5x more secure with less characters!

Your offline password cracker can crack numeric only passwords with ease. Heck, if you know who supplied the access point, you can narrow your search. For example I have uverse and I got a 10 number password by default, just like all uverse customers. So if you know its a uverse customer you can tell your cracker to focus on 10 digit permutations. There's only 10 billion permutations there. With 10 lowercase letters its 141 trillion.

randomdata• 14 years ago

Sounds a lot like my bank. 5 characters of 0-9 is exactly what they validate their passwords on. Luckily that validation is done only in Javascript, so disabling the check allows you to use any password you want. That doesn't help the average person though.

moxie5• 14 years ago

I run CloudCracker, so I can add some color. 'English' dictionary jobs use dynamic models built by password compromises from english speaking users, augmented by the results of our own jobs (as well as occasional brute force jobs we run against a sample of handshakes which didn't crack).

The smaller 'English' dictionaries focus tightly on that. The larger 'English' dictionaries include the longer curve of those passwords, but also start to mix in the hot spots from other models, such as valid NANP numbers (which is what got this example).

peterwwillis2• 14 years ago

People are still really surprised when I offer to crack their neighbors' wifi passwords for them - "You can do that?". We've only been at it for over 10 years now.

ryanmolden• 14 years ago

>What's more, WPA and WPA2 passwords require a minimum of eight characters, eliminating the possibility users will pick shorter passphrases that could be brute forced in more manageable timeframes

Should I point out that 'password' is 8 characters :) Have there been studies done that attempt to test the hypothesis that when forced to pick passwords that meet some arbitrary complexity threshold most common users pick things like "password1"? I have a hard time believing most non-techies (heck, even a lot of techies) pick secure passwords.

chimeracoder• 14 years ago

Anecdotally, most people I know without secure WIFI passwords pick things like:

- Their address (sometimes with numerals spelled out)

- Their last name

- Their child's name

- single (common) dictionary word

- single (common) dictionary word + one or two digits.

simba-hiiipower• 14 years ago

for about 80% of protected home networks i’ve accessed the password ends up being someone in the home’s phone number.. not sure if it’s just because it’s often the only 8+ character string of numbers people readily have memorized or if it’s just lazy isp’s that set it that way (and lazy owners who never change it afterwards)..?

commandar9• 14 years ago

One of the things I try very hard to drive home to people is that WPA2 uses a passphrase and not a password.

I highly encourage people to use something like a favorite movie quote or a line from a book. Something like "Alas, poor Yorick! I knew him Horatio;" is both harder to crack and easier for a human to remember than something like "v3$bk:j".

You're essentially taking natural language, which is something humans are pretty adept at remembering, and turning it into a direct mnemonic for a more complicated passphrase.

lotharbot6• 14 years ago

The problem with movie quotes and lines from books is that they're out there in a database somewhere. That means they're not nearly as hard for a computer to guess as you might think.

Jare• 14 years ago

Obligatory xkcd: http://xkcd.com/936/

forcer3• 14 years ago

Don't really want to hijack this thread so feel free to downvote me if you feel its not appropriate.

We launched a product that protects you from these attacks - more discussion here - http://news.ycombinator.com/item?id=4444478

sil3ntmac2• 14 years ago

My review (of wifiprotector.com): dude, this looks like a virus. Spruce up the page! Give me some screenshots! Please, let me trust you!

tomwalker• 14 years ago

I agree- have a few "learn more" buttons, videos etc

forcer3• 14 years ago

Thanks! The download link goes to CNET download.com where they make sure all software is trusted. but I understand we should improve the page so people actually feel reassured before they click on download.

mikemoka• 14 years ago

Correct me if I am wrong but the solution proposed is to use a free vpn under your control, my question is why do users have to trust you with their data?

pc86• 14 years ago

Am I the only one that's bothered by seeing that red dotted underline for ANonce, SNonce and Ack?

smackfu3• 14 years ago

No, you would think an editor would notice that kind of thing.

guilhermetk• 14 years ago

>To capture a valid handshake, a targeted network must be monitored while an authorized device is validating itself to the access point.

I think it's a really noob question, but how do you monitor a network if you are not connected to it?

coob• 14 years ago

The same way you tune into a radio station, these packets are in the air for everyone to see.

Many wifi chips can be put into 'promiscuous mode' which allows them to monitor a channel and capture all traffic on it.

Zenst• 14 years ago

Its wireless so the same way you can overhear two people talking.

efraim• 14 years ago

The network card sees all packets that go through the air but discards the ones not meant for your computer. Unless you tell the card not to which is called promiscuous mode, then all the packets are available to the OS.

rvid2• 14 years ago

You're also screwed if you have WiFi Protected Setup enabled (Its enabled by default in most routers). Once can easily crack a WPA2 passphrase easily in a few hours using a tool like reaver.

ohashi• 14 years ago

Care to elaborate?

rvid2• 14 years ago

Look here: http://sviehb.files.wordpress.com/2011/12/viehboeck_wps.pdf

And here's a link to the tool: http://code.google.com/p/reaver-wps/

chadyj2• 14 years ago

What is the command for aircrack-ng to generate the pcap file with the handshake?

(For those curious mac users, you can simply type "brew install aircrack-ng")

eli• 14 years ago

Note that (I think) Apple typically uses Broadcomm wireless chips, which are not the best choice for this sort of thing.

chadyj2• 14 years ago

So far I have been using Macstumbler in passive mode, but it takes a long time. So far I have only hacked my own test 12345 password

projct• 14 years ago

Many modern MacBooks use atheros chips, which work perfectly.

freshbreath• 14 years ago

That will install 'aircrack-ng', which can crack WEP ivs packets or a WPA/2 handshake.

You will need airodump-ng to actually capture the handshake. I don't think the entire aircrack suite has been ported in homebrew.

phusion• 14 years ago

As one of the comments mentions, you can bypass this whole step by using Reaver, which attacks the WPS pin number instead of the encryption scheme. It's not 100% and it takes 8-12 hours to complete, but it does work.

nickpresta• 14 years ago

So what do I run now instead of Kismac, since it doesn't support anything > 10.7.2? Aircrack with some GUI frontend?

gjulianm• 14 years ago

A Linux distro.

Don't get me wrong, this isn't an anti-apple rant: I've myself tried to my Macbook laptop to learn aircrack and finally desisted. The most important tools, airodump and aireplay, don't work in Mac, even if you have an injection-capable card.

Your best option is try with Linux either in your Mac (I think Backtrack has a Live CD so you don't have to install anything) or in a non-Apple PC.

syassami• 14 years ago

& A simple remedy for staying on your mac is to use a wireless dongle (USB) that supports packet injection. It's extremely simple to set up in backtrack.

soperj• 14 years ago

Or just use a virtual machine instead of running off the live cd.

scott_s4• 14 years ago

No doubt, this neighbor should have changed his password long ago, but there is a lot to admire about his security hygiene nonetheless.

I think it's taken too much for granted that one should change passwords on a regular basis. If we assume that changing passwords more frequently means that we are more likely to use more rememberable - and, thus, more guessable - passwords, then perhaps this is not a fluke. Perhaps "pick a truly random, long sequence and keep it for a long time" is not actually bad policy.

In short, I find it odd that the author unquestionably says his neighbor should have had different password behavior, yet it was the only password he couldn't crack. That's an opportunity to revisit assumptions.

Xurinos• 14 years ago

One should change passwords on an irregular basis (a regular basis is weaker protection than an irregular basis). This is just an additional layer of security, not a perfection. If the password has ever been compromised, a password change policy removes the key from bad hands. Discovered passwords are not always immediately used; in many situations, they are stored for later use, perhaps even sold/traded.

scott_s4• 14 years ago

We shouldn't make such proclamations based on reasoning along. Security policy that involves human behavior depends extensively on what humans do. So while a particular security policy may be the safest, most rational thing to do, it may fail in practice if people execute it poorly.

So, if it is true that when people regularly change their passwords, they pick poorer passwords, then perhaps those poor passwords are a larger risk than the risk of maintaining a compromised password. Again, this is not a question of what is the most rational policy. It is a question of human behavior, which means in order to find an answer, we need to study what people actually do.

I googled to see if I could find studies on this, and I did: "The True Cost of Unusable Password Policies: Password Use in the Wild" by Philip Inglesant & M. Angela Sasse: http://www.cl.cam.ac.uk/~rja14/shb10/angela2.pdf I have yet to read it in full, but they do touch on this idea at least some.

InclinedPlane• 14 years ago

How often do you rekey your house?

thezilch2• 14 years ago

If we are talking about system passwords (router or otherwise), there's a good chance you'll just be left with something malicious (ex. key logger) that is going to render null your irregular change of passwords. Regardless, irregular updates is just another form of security by obscurity. What if your password is cracked at the beginning of an irregular cycle?

The only reason one should have to change their password is if it is significantly weak -- "crackable" -- or they enter it manually -- it is visible -- in front of others a significant number of times for them to "record" the strokes. Good password managers, more or less, solve both cases.

thezilch2• 14 years ago

If using a significantly good password, from the beginning, it is pretty unlikely that anyone would go through the trouble or have the opportunity to watch you enter your password. To me, it only makes sense to change a WiFi password for the following reasons:

a) you care if people are using your network, or you do not simply keep track or whitelist-only of machines that have negotiated with your router

b) you use a short -- "crackable" -- password

c) someone can peer into rooms were they might spy on you entering your WiFi password

d) (c) happens enough that they can make out the whole password

For typical passwords -- desktops, laptops, email, etc -- it makes sense to change passwords (and use a password manager), but only for those things that really matter. Otherwise, there is probably not a lot of undo-able harm that can come of someone having access to your account(s) on <forum du jour>.

mgualt• 14 years ago

A couple of naive questions about the design of the security system:

1. Why is it possible to do the password tests remotely? Why would the key on the router be allowed to be transmitted? Even a 6 character password should be safe if you don't allow multiple tries.

2. Why isn't the handshake protocol encrypted?

jdthomas• 14 years ago

1. The attack is to brute force the shared secret (password). This can be done offline because by capturing the exchange you have the ANonce and SNonce and all other information required to generate the same key -- except the shared secret. Try lots of passwords and check if you generate the same PTK as the two stations do.

2. Encrypted with what? This is the key exchange stage that is attacked here.

802.11w adds signing to management frames which eliminates the deauth attack -- makes it harder to capture the EAPOL frames. Also, IIRC, WPA2-enterprise would not be susceptible to this sort of attack; you've pre-shared a key rather than a (short) password for generating one.

edit: spelling

delackner• 14 years ago

Honest question: since all devices connecting to a WIFI network are by definition within a short distance of the router itself, is there a WIFI solution that uses pre-shared key cryptography? That seems to me to be the only truly unbreakable option.

caspianm• 14 years ago

Password authenticated key exchange should do what we want. I was hoping WPA2 would have have used it already.

http://en.wikipedia.org/wiki/Password-authenticated_key_agre...

MichaelGG• 14 years ago

The key isn't being transmitted, but a hash of it with a nonce is. You could do a DH key exchange and encrypt it, but I doubt that would help that much: An attacker would just need to transmit their own auth packets.

praveenhm• 14 years ago

This is very interesting read.

smackfu3• 14 years ago

I would place good money that most AT&T wireless routers (SSID = 2WIREXXX) are using the same 10-digit password that is printed on the sticker on the unit. Yes, it's more secure than the old days of a default password being "default" or "admin" but not so great if 10-digit passcodes are easily broken.

moxie5• 14 years ago

It's a pretty big keyspace, but not quite big enough these days. I haven't noticed any lack of uniformity across it, but I don't really have enough samples yet to be sure. We have a dictionary specifically for those devices, just because they're so common: https://www.cloudcracker.com/dictionaries.html

smackfu3• 14 years ago

Very cool. The obvious question I have after looking at that is why the largest 2WIRE dictionary has 4.8 billion entries when the keyspace is 10 billion. Is the keyspace really not all 10 billion, or is there a 50% chance my key won't be in the dictionary?

zerohm• 14 years ago

I found this article to be a bit sensational. It should be titled, "how I paid some experts to crack my neighbor’s Wifi." I’m not trying to dismiss the threat, just put it in perspective. The use of these tools is either expensive ($2500 a year?) or requires a non-trivial amount of expertise (Aircrack-ng).

I did find the article linked within to be more interesting and informative.

http://arstechnica.com/security/2012/08/passwords-under-assa...

moxie5• 14 years ago

There's also an in-between. Many CloudCracker users employ tools like KisMAC (which are fairly user-friendly) to get a capture, and then simply upload the output to CloudCracker (also fairly user-friendly).

ctdonath4• 14 years ago

When addressing various physical home security issues, I came to the realization that if a trained team of attackers equipped with body armor and night vision broke into my home, the issue escalated beyond anything I could sensibly prepare for.

The article reminded me of that. If someone attacks my home wifi with network sniffing hardware, sophisticated password guessing tools, hours of planning and execution, etc then, well, the issue escalated beyond anything I could sensibly prepare for.

I realize these computing tools are easy to come by and not terribly hard to use. Ditto body armor, night vision, and combat training. And if someone is inclined to apply them against my pathetic existence, I'm screwed. Planning for such events is pretty pointless, I have other things to do.

brigade• 14 years ago

A physical assault carries a high chance of being noticed, and unless carried out by law enforcement, a significant chance of being punished with jail time. So it's not something that has a high chance of happening. Additionally, it's hard to defend against, and you definitely don't want to defend against a SWAT team.

Whereas a bored teenage neighbor could attack your wireless network with a very small chance of being detected. Or with a sensitive directional antenna it doesn't even have to be your neighbor if the goal is just to sniff traffic. Plus, the only cost to you in defending against this attack is entering a more complex password on new devices. Stick a note on the fridge or choose a phrase.

SiVal2• 14 years ago

I'm no security expert, but after I saw each new wifi password standard cracked within days of its release, I stopped passwording my wifi and used a little script I put on a home linux server to watch the router and if it spotted any unrecognized MAC addresses getting an IP address from DHCP, it would throw them out within a few seconds.

These days, I just turn on the MAC address filter that's built in to most wifi base stations. Now, unless I've manually entered your MAC address into my whitelist, my router won't connect you. My wifi shows up as "open" to any machine that passes by, yet it won't connect.

Many (most?) of you know more about security than I do. How secure is the MAC address whitelist approach compared to a password approach?

ctdonath4• 14 years ago

a bored teenage neighbor could attack your wireless network

He would have to be very bored indeed. Singling out my home to spend considerable time at an inconvenient in-range location to crack passwords to access ... what, exactly? view pictures of my toddlers? copy my slightly deranged music collection? If he's looking for free network access, he can go down the street and get it from McDonalds or Starbucks or wherever while sitting in a comfortable chair sipping a soda.

I realize a bored teen is different from a SWAT team. Both, however, would need unusual motivation to turn their talents on my abode.

Dylan168072• 14 years ago

>network sniffing hardware

a large fraction of normal wifi devices that can be set into a proper receiving mode

>sophisticated password guessing tools

some password cracker they downloaded in minutes

>hours of planning

pressing a button or typing a couple commands

>and execution

taking a nap

It's not hard to secure a network from extremely simple attacks. At least for now.

And that analogy is nonsense. Body armor, night vision, combat training don't help them break into a house. At best it'll get them past the armed guards you don't even have.

ctdonath4• 14 years ago

The analogy is fine.

Walk into a well stocked military surplus store and you can walk out with all the tools you need to break into a house in short order, and trust me it doesn't take long to learn how to use them well enough.

The point is that once someone is determined enough to get into either your home or network, it doesn't take much to reach a stage where the owner has to go to great lengths to resist a very unlikely occurring, but very likely successful, attack.

frankus2• 14 years ago

My strategy is to use a human-readable password for my guest network (which I actually considered leaving completely open), and a crazy-long random password that I copy and paste from my password manager for my internal network.

robertskmiles• 14 years ago

Why did you decide not to leave it open?

frankus2• 14 years ago

I felt like it would make me responsible for monitoring it for abuse.

It could be something as innocent as a cheapskate neighbor using enough bandwidth to run afoul of my cap, or someone using it for nefarious purposes either on a continuous or drive-by basis.

laxk• 14 years ago

Is there way to measure WiFi signal quality between router and connected devices? any API on linux side? An easy generic protection can be done in the following way (if there is api): Ban all unknown MAC addresses with WiFi signal quality below the specific treshhold. In that case if hacker decides to use fake MAC address he cannot fake signal quality on my side.

Does it work?

icebraining• 14 years ago

You can measure the signal quality, but that doesn't buy you much. If you only ban unknown MACs, then he can just clone yours, and signal quality is easy to evade with a cheap (< $20) higher gain antenna.

In my home, I often get a better signal using my laptop with an external antenna two walls from the AP than with my phone just a couple of meters away from it.

recursive• 14 years ago

The only reason I even have a password is on my router is that it crashes more often under traffic if I leave it open. I intentionally made the password easy to guess.

X-Istence2• 14 years ago

That is why a passphrase is so important. No longer it is a dictionary word, now it is multiple dictionary words together.

debacle• 14 years ago

Was it correct battery horse staple or battery horse correct staple?

I use passphrases almost exclusively. The key is picking words at random - phrases are easy to guess, though sometimes I pick them because, to me, they're easy to remember.

"Areyouopposingshadowmoon?" is an incredibly secure password, and it's very likely that no one would ever 'guess' that phrase, but it's also highly easy to remember (because 1997 engrained it into my head).

X-Istence2• 14 years ago

I use things I remember from movies/books. Stuff that has always stuck in my head to the point that there is no way for me to forget it.

koevet• 14 years ago

I have successfully cracked a couple of Routers using Reaver. Reaver Leverages a bug in WPS (wifi protected setup) http://arstechnica.com/business/2012/01/hands-on-hacking-wif... It's way faster than brute force or dictionary attacks.

stonefroot• 14 years ago

re: MAC spoofing

I don't use WiFi as a matter of practice, but I'm curious: What if you could keep all the "whitelisted" MAC's continually logged in to your network, or, at least, you could keep track of when they log out. The idea being that MAC spoofing is not possible if the particular MAC that the attacker wants to spoof is currently logged in. This is generally true with Ethernet, correct? Is this true with WiFi as well? (Assume the traffic is encrypted.)

And in fact, it seems this guy's hack relies on someone "rejoining" the network, triggered by a deauth frame. Without that "rejoining" step, I don't think he could get very far. If his target is continually connected, and there's no way to force a "rejoin", and all the traffic is encrypted, then what can he do? The problem to me sounds like the fact that someone can send a "deauth" frame and have it be accepted, and the Apple Mac gives no warnings that the connection underwent a "rejoin".

olalonde• 14 years ago

> To his chagrin, it took CloudCracker just 89 minutes to crack the 10-character, all-numerical password he used, although because the passcode wasn't contained in the entry-level, 604 million-word list, I relied on a premium, 1.2 billion-word dictionary that costs $34 to use.

There are 10 billion (10^10) possible 10-character all-numerical passwords. Can anyone explain how it was cracked using a 1.2 billion-word dictionary?

githulhu• 14 years ago

Maybe they assume that a 10-number password is likely to be a phone number, and so constrain the three most significant numbers to just valid US area codes. Add in other rules, like the fourth digit never being a zero, etc...and the space is pared down quite a bit.

How I cracked my neighbor's WiFi password without breaking a sweat

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