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"Double-click on someone, and you're instantly logged in as them."

Ouch. I think it's time to set up that VPN I've been putting off...

Am I the only one who thinks this is spoon feeding the script kiddies to cause mayhem?
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Well, hopefully it will then convince companies to properly secure their websites and actually protect users.
Agreed, but I still think giving someone else full control is a bit too much. It's not the user's fault (most don't even know this is happening) and they're likely to be the victims here.
This vulnerability (it hurts to even call it such at this point) has been around for years, and the attack has always been easy for a determined attacker to carry out.

How else are we going to convince people to secure their sites and protect their users? People have been presenting on this issue for years (Ferret & Hamster, Blackhat 2007) and companies haven't responded/cared. It's possible to solve this problem (Gmail is all HTTPS, and done correctly, Amazon has a tiered authentication system that properly uses SSL for important things, Wordpress does SSL right for accessing their admin interface) - companies need to step up and address the issue.

Definitely, I guess as a uni student, I'm worried about the majority of non-technical students who are going to have their sessions hacked and have no clue what hit them and cannot setup proxies/tunnels.

I'm not saying this isn't the site's fault. They definitely need a wake-up call.

The problem goes beyond client-website interaction. Improper wifi configuration also plays a big part in what Firesheep can achieve. ;)
This was already happening on a massive scale before this new app was released... I honestly don't think it will increase the number of attacks by all that much. It's brilliant as a tool for spreading the word though.
It was happening on a massive scale, but now a huge amount of really lazy people who didn't bother to do this before are. It had 3,000 downloads after 2 hours of release. The thing is, most universities have protection set up. It seems Cisco NAC is actually good for something. I never thought I'd say that. The extension certainly doesn't work on my campus.
It should be noted that Wordpress implements SSL for wordpress.com correctly, but any self-hosted blogs from wordpress.org need to be individually configured.
This is essentially the same argument that comes up with full disclosure. Yes, it's not pretty. Yes, it causes a lot of collateral damage. But it also makes the big players patch things up faster, while letting the knowledge out to the public, which of course consists of not only the script kiddies, but also the unsuspecting legitimate users.
Even the dumbest script kiddies have been doing this for years anyway. There are plenty of existing tools. This one just lowers the bar so your mum can perform the attack too.

It almost makes me angry that websites like Facebook and Twitter don't force all traffic over https. They've got the money and the expertise. They just don't care if your account gets sniffed and taken over at a web cafe.

Exactly. I'm not a blackhat and my only "hacking" consists of forcing myself into my own systems which I've stupidly locked myself out of, yet I've managed to do much that this plugin can do.

The most un-ethical thing I have done was to take one of the OLPC XO laptops and convert it into a MITM machine, rebroadcasting the SSID it connects to while routing and logging all traffic anyone who connects to it generates. It took a weekend to setup using pre-existing tools and scripts and can be deployed anywhere I want within 2 minutes and run for up to 6 hours hidden in the bottom of my backpack. It was a fun experiment, and surely made me more aware of just how vulnerable I was outside of my home network.

Another point of interest, this weekend I hacked on a Minecraft bot for the Alpha version. In order to understand and dissect the connection protocol I needed to recreate, I used wireshark to dump and parse how the client authenticates and connects to the server. Even that transmits your username and password in plaintext.

re: the OLPC, what were you running on it? I have one in my closet and I've been meaning to put something that isn't the stock software on there for a long time.
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This looks really cool. I can't wait to try this out. Very nice work, Eric.
Thanks! If you or anyone has any problems, email me (eric@codebutler.com) with the details.
On Mac OS X, it gives an error saying: Run --fix-permissions first.

Run with which command? and how?

I found the binary "firesheep-backend" in:

    ~/Library/Application Support/Firefox/Profiles/<profile>.default/extensions/firesheep@codebutler.com/platform/Darwin_x86-gcc3
I ran both:

    ./firesheep-backend --fix-permissions
and

    sudo ./firesheep-backend --fix-permissions
and it still asks me to run it with "--fix-permissions". I guess it's time to go digging around in the source to try and find out what it wants me to do.

EDIT:

After a bit of digging, I found out that running it with --fix-permissions really just chowns the binary to root then setuid's it. I don't see anything wrong with it on the surface, but I'll keep digging.

There is an another firesheep-backend at /firesheep-backend.dSYM/Contents/Resources/DWARF inside the Darwin folder. However this one wont run using ./

Any ideas?

I believe that it is a file containing debug info, not an actual program, so you can't run it.
I have the same problem, nothing I do works, it just tells me to fix the permissions...
I can't wait for this to become available for linux, good job!
I got it working by running firefox as root, I tried the --fix-permissions thing until I just gave-up.
Just so you know, that is a horrific idea security wise.
Yes, I know, but it's the only way I could test it... and it does work ;)
This just completely freezes my firefox. Can't even get firefox to start at all.. Any ideas?
I thought the title of this submission was slightly misleading. This is not a security vulnerability from within Firefox, it's a Firefox plugin to reveal security vulnerabilities in a wide range of websites.
Sorry if it was misleading somehow, this is definitely not a vulnerability in Firefox. It's a Firefox extension that makes it easy to execute HTTP session hijacking attacks.
To be fair that is exactly what I got out of the title and not that it was using Firefox vulnerabilities.
For what it's worth, I got that it was an extension or other Firefox tool. Your interpretation didn't occur to me.
I couldn't install it on FF 3.6.9 on Windows XP.
You need WinPCap installed. Just FYI.
What was the error?
"Firesheep 0.1 could not be installed because it is not compatible with Firefox 3.6.9."

And yes, WinPcap is installed. I don't think it should matter, but I'm running Windows XP on a VirtualBox.

Oh, you just need to update to the latest version of Firefox (3.6.11). Your version is out of date and not secure. http://www.mozilla.org/security/known-vulnerabilities/firefo...
Thanks. It works now with FF 3.6.11. Your extension is amazing.
What should happen if you use iPhone tethering? Could it top into the vast people on that network? (I have absolutely no idea). If this is the case, the internet will have a panic attack in 2 days max.
No. Cabled tethering to a cell phone only gives you access to your own packets. It's like a switched network where only packets addressed to you are sent to you.

On 802.11 wireless networks your wireless network card is capable of capturing traffic addressed to other computers. When encryption isn't used or is compromised, you can steal their credentials.

Doing something similar against cellular networks would require a much more sophisticated attack with specialized hardware that's largely illegal in the United States. I would also hope that cellular communications are encrypted these days.

Is there another application besides the FF extension to dump the packets and process them? How does this work?

EDIT: Sorry, I asking specifically how this FF extension works.

Nice. A solid demonstration to show next time your webmaster doesn't want to set up SSL everywhere.

That said, the current cartel-like setup of certificate authorities (protection money and everything!) makes SSL annoying and expensive if you want the browser to not have a fit. Especially for small-scale projects. But there's really no excuse for larger sites.

You can get SSL certificates for free for one domain, and they work with all browsers (except Opera, IIRC). Also, you can use Perspectives for Firefox, which I think is much better than the current system.
I've had a bit of a look on Google, but I'm not 100% sure which provider you mean? Where can you get free SSL certificates that don't upset browsers?
Ah, I can't remember the name now... Rapidssl? That's probably it. Check historio.us, the ssl cert there is a free one (which is, sadly, why subdomains don't validate).

EDIT: I searched and it's actually http://cert.startcom.org/.

Check historio.us, the ssl cert there is a free one (which is, sadly, why subdomains don't validate).

AFAIK this is common to all certs (free or otherwise). You need a separate one for each subdomain (including www).

No, there are also wildcard certificates that match all subdomains, but are rather more expensive.
Didn't know that, thanks.
Wildcard certificates are available for USD $49.90 from StartSSL (http://www.startssl.com/?app=40), which is rather more expensive than free, but shouldn’t be a hardship.
The only downside to wildcard certs through StartSSL is that getting one requires high-resolution proof of personal identity, to be kept on file outside local jurisdiction (the company's based in Israel) until the cert's final renewal or revocation, plus seven years.

I admire their model of only charging for operations which require human intervention, like identity validation, but handing over that degree of documentation for that amount of time requires a lot of trust, not just of the company as it currently exists, but as it will exist in the far future.

If there was a way to validate organizations which wasn't layered on top of an earlier validation of an individual, or if their decentralized web-of-trust was usable for class 2/wildcard certs, I'd be a big fan.

As it is, there's no reason not to use Start for class 1, single-domain certs, for which the validation is automated and reasonable.

Wildcard certs don't match the underlying domain, though. See, for example, dropbox.com instead of www.dropbox.com; they've got a wildcard cert and it's not valid for dropbox.com.
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Namecheap provides free ssl certificates for each domain you get through them.
Right, and even the paid ones can be had for well under $30/yr nowadays, which is pretty trivial.
There are levels of pay for functionality, like subdomains, and being able to issue your own certificates.

For instance, from Verisign: a 1 year Microsoft code signing certificate starts at $499 [1]. A top-of-the-line (from their main pages) web certificate for a single server for one year: $1499 [2]

[1]: https://securitycenter.verisign.com/celp/enroll/selectOption... [2]: https://ssl-certificate-center.verisign.com/process/retail/p...

edit: it would figure the links don't work. Just go to www.verisign.com and those are a couple clicks from the front page.

Off topic, but re: Perspectives. It allows your browser to compare notes with other nodes on the Internet ('network notaries') to ensure that everyone is seeing the same cert for a given website.

Looks like a great idea, but how do they prevent the man-in-the-middle from impersonating a network notary?

Notaries sign their responses, if I remember correctly.
SSL is bad for the environment because it requires far more server side hardware... Well, I'm only partially serious about the environment thing, the question is, how can internet companies make it commercially viable to use SSL for everything? The added hardware and power costs make each user way more expensive, possibly to the point where they may not actually be worth it.

An alternative is to bind the user's session to their IP address, but that isn't fool proof either because of NAT, DHCP and certain big ISPs that tend to change IPs on the fly.

What cost-effective solution would you suggest?

Require SSL on any request who's response sends a set-cookie http header. Leave it out for the non-sensitive request/responses.
You'd still be able to get the cookie when the client sends it bnack to the server on subsequent, non-SSL requests.

It's gotta be SSL all the time.

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When Gmail switched on SSL for everyone earlier this year they added "no additional machines" (http://unblog.pidster.com/imperialviolet-overclocking-ssl).

Regarding IPs, there's a bigger issue here. People are used to being able to shut their laptop at home and open it back up at work without having to re-authenticate all their browser tabs. If you filter by IP this breaks. SSL requires no changes to user behavior.

What about pairing the auth token with a browser fingerprint? [1]

It would make it harder to troll an open network for random victims, and wouldn't annoy the user.

[1] Perhaps a hash based on something like this https://panopticlick.eff.org/

yep then you extend it to something as simple as having a second ID in localStorage or a flash cookie

then the next version of this plugin just spoofs all of those parameters as well

the only solution[1] is SSL and client certificates

[1] in the case of being on the same network

interesting info in that url, thanks
People bring up the Google stat, but you have to remember they have incredible engineering resources so they probably optimize in many features every day without adding additional machines. That doesn't mean every dude with a LAMP stack out there can turn on SSL and expect the same performance, just that it's possible with mongo manpower and talent to make it work. (Google doesn't even release the details of their web stack so comparing their stat is apples and oranges.)
How many web servers do you know of which are CPU bound, and not through massive code stupidity, and not I/O (in some manner - waiting on SQL, disk access, bandwidth)? Encryption can run while other threads are waiting for a response.

In general, it's a negligible cost; it adds a very minor delay compared to latency / transfer time, and uses CPU otherwise highly unlikely to be pegged. If you're pushing threading limits / CPU usage limits, you're probably inches from needing new hardware anyway, and SSL should be considered part of the cost of running a web server.

It's not completely negligible--even if CPU usage is negligible, it does add latency during SSL negotiation that might be unpreferable for some apps. The testing burden is a lot higher because one wrong link to http:// in CSS, HTML, or AJAX will cause big scary messages. And there is the IP address problem, you can't vhost as most people with Apache like to do.
That may have been true 10 years ago, but the overhead of SSL for CPU is almost nothing, and only a few ms of latency. Web applications are mostly IO and memory bound, anyways. We should be using SSL all the time, by default. There's no reason not to, at this point, aside from certificate authorities.
Startcom offers free no-BS certificate signing, and their CA is on most modern browsers, I believe. I think they could be suitable for small scale projects.
HTTPS also needs distinct IP addresses for distinct hostnames, so that the HTTP handshake, in which the Host: header appears, is already protected by an encrypted channel. No more having multiple websites on one IP address.
That's an incredibly drastic change and I seriously doubt it can even be done with IP4.
There's TLS 1.1 SNI extension which adds vhosts.

Works — of course — everywhere except IE6/7XP.

The sidebar is not showing up for me after installing and restarting.

Firefox 3.6.11 OS X 10.6 firesheep-0.1-1.xpi

Same setup. Sidebar shows for me after selecting it from the View -> Sidebar menu, however it pops up with a message that says "Run --fix-permissions first." Not sure where I'm supposed to run this flag.
Same error for me. No idea where to run though.
There is so many hoops I have to jump to make this work in OS X.

$ mv firesheep-backend firesheep-backend.binary $ cat > firesheep-backend #!/bin/sh sudo /path/to/firesheep-backend.binary $@ ^D $ sudo chmod +x firesheep-backend

Then restart Firefox and start capture. You need to run sudo once every certain period.

It worked instantly for me on OS X. I installed, restarted the browser, and it opened the side panel.
I keep getting a "Failed to fix permissions" error. Any insight into that?
Wow, good work. And pretty scary- imagine what one could do with this on any college campus.
A guy I know used to do this in airports (just for fun, didn't do anything malicious) by grabbing webmail logins. Running wireshark with some simple filters and watch the cookies roll in.
Interesting. I was going to do something similar but keep it limited to Facebook chat. That way you could eavesdrop on conversations in the room and impersonate people, etc. This is actually probably easy to program and more versatile at that.
On the other hand, stealing somebody's real life identity is not that hard either. But it does not happen too often, in part because it's illegal. Stealing somebody's cookie on the Internet is a crime just as is stealing somebody's driver's license. Although technical solution to this security hole is desirable, it's not the only solution available.
Thanks to the EFF and the Tor Project we need not worry as much thanks to their HTTPS Everywhere project, a plugin for Firefox: http://www.eff.org/https-everywhere/

Any questions:

http://www.eff.org/https-everywhere/faq

Logging into insecure sites over Tor is probably not a good idea. It's always good to assume that people running exit nodes are not the most trustworthy.

HTTPS Everywhere is good but only works on known sites (and known domains for those sites).

HTTPS Everywhere only works on a select few sites. You're up a creek for anything it doesn't cover.

And Tor, there's lots of cases where operators did bad things. Don't trust it for sensitive information. http://blog.ironkey.com/?p=201

I highly dislike the title of it. It is not HTTPS everywhere, it is "HTTPS on sites we know it is possible on".
I realize I should of put more emphasis on "as much" as yes this only works on only a few popular websites as defined by the plugin.

Thanks to reading Techcrunch this morning, I read about this plugin which allows you to manually define which sites you want to force an HTTPS connection on:

Force-TLS https://addons.mozilla.org/en-US/firefox/addon/12714/

Mind you for any of these extensions to work the website you're visiting needs to be already accessible via ssl. If the site does not have encryption, these plugins can't force the sites to automagically start using the encryption it never had.

What can an end user do to minimize this?

This exploit is for insecure Wifi networks- so only using encrypted Wi-fi or Ethernet would seem to remove this attack vector. Is there a real risk that someone (besides the government) can see your cookie?

vpn/ssh tunnel/encrypted wifi
Encrypted WiFi won't stop clients on the network from sniffing your packets.

It will, however, stop unauthorised computers from sniffing any network data.

I would have expected each wireless client, on an encrypted network, to negotiate its own key with the access point -- so you'd only see neighbors' traffic if the access point chose to rebroadcast it to you.

Are you sure that neither WEP nor WPA/WPA2 do it this way?

The encryption is between your client and the AP. Uaually everything after that is standard IP.
That's what I thought -- enough to protect against fellow wireless sharers, but not the hosting establishment or path through their ISP to a website.
No, you misunderstood. It's enough to protect you against random people sniffing wireless packets. Not other people that are on your network.
Your terminology "the network" or "your network" is still unclear; encryption to the AP could be unique per wireless network client, or not. If it is unique per client -- and it is my belief that recent standards, like WPA2 at least, provide this -- then casual passive eavesdropping by other wireless clients (as with the FireSheep tool) is thwarted. (And that's what most people are most concerned about.)

Are you suggesting that no generation of WEP or WPA protects against other authorized wireless users of the same AP, because they're "on your network"?

[rewritten completely to seek clarification]

WPA enterprise allows a separate (changing) key for each user, typically what you get from an RSA token. Once it gets to the AP, it's then clear text (assuming HTTP) over the rest of the internet until it hits your (HTTP) service provider.

If you have control over the internet between the AP and your server, then you're safe. If you don't, then how safe you are depends on how much you can trust the owner of each router along the way. In general, you should be okay, except that every now and then you might end up on an untrusted router, and it's then game over.

Sorry, did not follow this part - "Not other people that are on your network.". Care to elaborate?
Is there a real risk that someone (besides the government) can see your cookie?

Yes, if you login and your cookie is sniffed and spoofed then basically you just allowed the attacker to login as you at the same time.

Minimizing it is a little bit different: you can use a secure proxy/tunnel, you can limit your unencrypted wireless activity, you can make sure that sites that should be SSL encrypted are (stripping SSL is common when password sniffing) and you can avoid these services while on open wifi networks.

logging out will cause the captured sessions to be useless.

So remember to logout.

VPN is really the best overall option.

That assumes the session is killed on logout. I know from first-hand experience that at least one version of Merb didn't do that. I hacked a pretty popular geo-socially site by grabbing the session cookie and playing around, then logging out. Was still able check-in after I had logged out and for good measure verified that my session was still valid after changing the password. I assume they were using the default sessions setup so I guess it expired. Didn't keep it around to see how long it stayed around.

On reporting it, the response was essentially, "oh you didn't have to go to that much trouble, you could have just used your user/pass from curl…" Completely obvious to the fact that they're app/site was completely vulnerable to session hijacking.

One of the problems of app frameworks, if you don't know what they're doing (and more importantly, not doing) you can get yourself in a heap of trouble before you even realize there's an issue. But boy, you sure can make it to market fast. shakes head

Most sites don't properly invalidate sessions when you log out, you can't protect yourself as well as you think. See our slide on this topic:

http://codebutler.github.com/firesheep/tc12/#18

Excellent points on the slideshow. The general lack of care on this topic among web companies is worrisome.
Just tried it with iGoogle

Logging out doesn't kill the session.

Why don't Facebook and other major sites check the user agent and IP address of client as well, instead of just relying on a cookie? That would solve this problem in 99% of the cases, right?
If you're on the same wireless network as someone, you have the same external IP address.
And of course, if you can see the traffic, you can spoof the same User-Agent as well.
I realize that but at least my neighbors won't be able to hijack my session from home. Logging in over a public network always seems risky.
Are your neighbours on your private network? If not, you don't need to worry about them capturing your network data, because they're not on the same network.
Plus, your source IP can change from request to request when your ISP transparently pushes you through one of many proxy servers. AOL does (or did) this, as do some large European ISPs whose names escape me.
Yet another reason NAT sucks...
The explanation I've always heard for not using HTTPS 100% of the time is that it puts an substantial load on the server, and for many sites it's overkill. Setting aside the subjective topic of "overkill" ... how much more CPU-intensive is it to serve pages over HTTPS compared to HTTP?
The cpu load can be mitigated with frontend https accelerators or proxies (think nginx as a load balancer doing the https). The real problem is the first connection. Browsers don't fall back to https, if nothing answers on http they'll give an error. If the first connection is over http then a man in the middle attack can succeed.
> If the first connection is over http then a man in the middle attack can succeed.

There are ways to work around this, if the non-https site immediately redirects to the https version and a "secure cookie" (https-only) is exchanged afterwards.

Someone correct me if I'm wrong, but that's the exact vector point for a man-in-the-middle attack. First request over HTTP gets hijacked, redirected to a "secure" server, then you (the user) see the lock and go to town, secure in the knowledge that you're communications with this server are protected because they're encrypted.
Isn't that exactly why HTTPS sites are supposed to have expensive certificates issued by big companies? Otherwise the browser will display a big red warning message. If you ignore that warning, you deserve to be hacked.

If the request gets redirected to a HTTPS proxy site that the attacker has set up, that's a different story. But again, you should be checking what's in your address bar. No security system can rescue you if you can't tell the difference between "mail.google.com" and "mail.google.haxxor.com". But for those of us who actually read what's in the address bar, HTTPS is pretty good security.

Isn't that exactly why HTTPS sites are supposed to have expensive certificates issued by big companies?

There is virtually no cost associated with issuing a certificate. The fact that they are nevertheless prohibitively expensive for most private domains is partly responsible for the failure to adopt SSL on a broad scale.

Otherwise the browser will display a big red warning message.

While it is true that this warning is intended to protect users again man-in-the-middle attacks and other methods that redirect traffic away from the original source, it also prevents people with absolutely valid (but free) certificates from offering perfectly good encryption on their sites. This warning is misguided and does more to prevent the secure use of the web than anything else.

The remedies would be simple, but I guess commercial reasons prevent them from being adopted at the expense of everyday users.

> it also prevents people with absolutely valid (but free) certificates from offering perfectly good encryption on their sites. This warning is misguided and does more to prevent the secure use of the web than anything else.

Accepting self-signed certificates would not be a good solution. Anybody can sign a certificate with "www.facebook.com" in the Common Name field. Your communication would be encrypted, but you'd be communicating with the wrong guy. SSL was designed to provide both encryption and identification. Self-signed certificates provide only encryption.

Besides, certificates are already quite cheap if you know where to buy them. RapidSSL costs as low as $12/yr, which is just slightly more than the cost of a domain name, and it's recognized by all browsers including IE6. I wouldn't consider it "prohibitively expensive" if it costs less than two lunches.

There are, of course, many other ways in which the existing infrastructure is inadequate. Take a look at the list of CAs that your browser automatically trusts. It's a mess. But it's not easy to implement an alternative that can provide both encryption and identification with the degree of reliability that the current infrastructure has. Some kind of social trust mechanism might work, but we're a long way from standardizing on anything of the sort.

The CPU intensive part of a HTTPS connection is the initial key negotiation/session setup (using asymmetric encryption methods). The symmetric encryption of the actual traffic is pretty trivial.

You can amortise the session setup cost by ensuring the HTTPS session caching is enabled on your server (in Apache, the directive is SSLSessionCache). This will let subsequent connections from the same client re-use the same SSL session.

ooh, SSL DDoS
That possibility is why it would be nice if client puzzles were part of the SSL protocol.
There was a great write-up of a talk on SSL/TLS performance at Google linked here a few months back (http://unblog.pidster.com/imperialviolet-overclocking-ssl, HN discussion at http://news.ycombinator.com/item?id=1485425)

Quoting from that, "On our production frontend machines, SSL/TLS accounts for less than 1% of the CPU load, less than 10KB of memory per connection and less than 2% of network overhead."

OK, that's most likely too late to contribute to the stated article, but there was a talk by Michael Klishsin about a year ago, here're his slides: http://bit.ly/90qORL (ssl, performance, certificates, lots of stuff)
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This is kind of a big deal. Not a whole lot of people are aware of this vulnerability and among those who are it's likely only a small subset that knew how to exploit it until now. I suspect all of the coffee shops in the college town where I live will have people using this starting tomorrow.

I've personally been working from cafes and tunneling everything through SSH for years, but in my experience almost no one else does this.

I've personally been working from cafes and tunneling everything through SSH for years

To where? I suspect it's to a server, VPS, or similar, and the connection is unencrypted from there to its endpoint. This being the case, could someone with a server on the same subnet be running a browser remotely (or even just tcpdump) and doing a similar thing with your logins?

(This is just some thinking out loud and I may be totally wrong - correct me ;-))

If you control the remote network, it's a lot safer than having all your traffic unencrypted on the Starbucks Wifi.
It depends on how secure the remote network is. If it's just another coffee shop, you're screwed. If it's your own Linode in one of those well managed datacenters, it would be pretty difficult for anyone to snoop that traffic.
Virtually no modern wired networks use hubs anymore, they're for the most part switched. Unlike wireless networks where packets are broadcast freely in to the air, the switch checks the destination address and sends the packets only to the endpoint. There are some attacks like arp-spoofing and flooding which can defeat this, but they don't work well against modern enterprise-grade switches like you would find in a data center.
Have a bazillion karma points. I didn't realize that switching resolved that whole problem. This is why I continue to bring up stupid hypothetical situations on HN from time to time ;-)
Switching doesn't resolve the problem completely. There are a range of complicated attacks that could be done, but can be detected in various ways in a well run NOC.
But we're talking a lot more complicated and deliberate than running tcpdump or this Firefox plugin, right?
I guess if you really wanted to you could run a GUI tool like Cain (http://oxid.it/), but most people doing this type of thing would use something like Scapy or at worst, Yersinia.

So I'd agree, more complex definitely, significantly not as much perhaps (it depends on the type of attack as tool), as for deliberation I'd say about the same as the firefox plugin.

If you do run tcpdump you do pick up broadcasts and such, one of our VPS instances actually sees a load of DNS traffic for our subnet, which we think is the other VPS instances.

Exactly. That's why the net effect of this is going to be exactly what the author wants. All major potential targets will update this really fast.

I can't think of a more effective way for him to convince them all to update now.

You can slightly reduce the dangers stated here by logging out immediately after you are done doing whatever it is you are doing. This will make the captured session useless.

The best solution is of course to get a VPN acct and use it when you are at free/open wifi spots. I use WiTopia (www.witopia.net)

Or just get a mac mini server that will run vpn 24/7
Be careful when trying this out. You could be breaking a law or two...
Also don't web-mail your friends to tell them about the new accounts you just broke into :) At least not on that open wireless connection.
Good thing GMail has SSL enabled by default ;)
Yup, they're one of our examples of a "good" setup. However, Google leaks iGoogle and some other things (Latitude, address book, reader, ...)
However they don't share the same session cookie for different service as far as I know (which they negotiate that through TLS protected link) Likewise they have also made several other services TLS only (e.g. calendar, docs)
Makes a strong case for everyone to start tunneling their traffic back to a trusted network.

I've been trying out sshutttle <http://github.com/apenwarr/sshuttle>. It only tunnels TCP traffic, so you still have DNS and UDP traffic on the local network.

Has anyone checked the source code to check that the passwords aren't sent to the author's website? :)
Passwords are not a part of this... It's the session cookie, which is an entirely different matter. It's unique to the login process, so one compromised account isn't able to lead to compromising other websites. It's also time sensitive (generally) and so that hijacked cookie will expire. If he were collecting all this information, he wouldn't be able to do much with it.
Just because the user interface only exposes cookies, doesn't mean that passwords aren't captured and sent somewhere.

It's very possible, given that the extension seemingly captures HTTP requests/responses. If passwords are sent or received in plaintext, then they can be captured.

It's 100% open source! Please feel free to review it.

http://github.com/codebutler/firesheep

It doesn't currently do anything with passwords, it's only pulling out cookies from HTTP Response headers. But it would be trivial to also get passwords in non-HTTPS requests for logins with the same method.

Indeed. Sorry if I implied that you were doing evil things.

People should also be aware of the security implications of installing various software on their system. :)

Again, not assuming you're evil, but it's possible that the compiled binary (.xpi) was not created from the source posted on the github account :)
Not sure why you're being downvoted, seems like a legitimate question to me! I was a little leery of checking it out at first, too, but curiosity got the better of me...

Maybe someone who has developed a FF extension can lay my worries to rest -- could this have, say, a built in key logger which sends that data to the author?

I downloaded the source code from github and glanced through it, enough to comfort me somewhat, but I wasn't super thorough.

All that said, EricButler seems to be an HN member in good standing, and someone like that wouldn't do anything malicious, right? :-)

>> Maybe someone who has developed a FF extension can lay my worries to rest -- could this have, say, a built in key logger which sends that data to the author?

If it could sniff packets on network interfaces why couldn't it send data to a website? ;)

This kind of FF plugin requires extensive C++ coding. But even simple plugins that are only JS could easily send your username and password (if entered within them) to any web server.

Doesn't work in 3.6.4, even if you override install it or change the minVersion (which is 3.6.10)

Once I upgraded to 3.6.10 worked awesome.

Wow, I've been wanting to do this for a while to raise awareness. Great implementation by plugging it into Firefox - well done.