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Public Access 'Blackspots'
WeakGeek writes "Unstrung has a story talking about a security issue with the combining of 802.11 and GSM/GPRS networks. Seems that 802.11b hotspots provide hackers with an easy way to grab user information from the wide-area network itself.
Back when GSM was being defined, standards were designed to only authenticate the details held on the SIM card in a user's device before starting a session on the network. The user's device doesn't in turn check the credentials of the network. Fake a network, get data.
Of course, the linked to story seems to be a 'viral' advertisement for a product that fixes this, but I still thought it interesting enough to share."
if i recall.... WEP is the wirless encryption protocol. 802.11 networks should be rolling it out if its not already. Simple solutions? use an SSL gateway
"Martha Stewart can lick my Scrotum......do i have a scrotum?" -- Sharon Osbourne
I guess the good thing is that not many phones are 802.11 capable. The amazing thing is that with 802.11 being so insecure that anyone would think adding this feature would be a good idea.
Manipulate the moderator system! Mod someone as "overrated" today.
'This all adds up to networks that could be vulnerable to hacker attacks, according to Schlumberger.'
What an amazing conclusion. Networks are vulnerable. Thank you once again, Captain Obvious.
"I only speak the truth"
Karma: null(Mostly affected by an unassigned variable)
from the article:
This all adds up to networks that could be vulnerable to hacker attacks
All networks are vulnerable, no matter how many precautions you take. Heck, just watch mission impossible again (if non-networked computers are vulnerable,...).
If ya don't read the article, check out WLAN: The Four S's, and a WEP FAQ.
--------
Free your mind.
And why would 802.11b fix this ? If you can put 802.11b there why not just put up a cell to fix the problem ?
Right now where are the 802.11b networks... for the most part they are in the cities. Where do you not have a problem with reception... in the cities.
Why would someone put an 802.11b network out on Route 100N in Vermont rather than just a cell on the top of the mountain ? I'm obviously Mr Thicky here as it does seem that if you are going to put up a wireless network you might as well put up one that is already supported by phones rather than adding more bulk to the phones with a seperate set of chips to drain the battery.
I've got bluetooth on my mobile, and GPRS. Someone please tell me why I'd want 802.11b as well ?
An Eye for an Eye will make the whole world blind - Gandhi
... it uses 3G, and is therefore not popular enough to be an immediate serious concern (unlike, for example, hacker attacks on products like Outlook, which are used by millions)
E000-VB14-G8RY
Maybe I'm missing the point :) but isn't this just a function of the fact that there is no user-level authentication in 802.11b at all... The fact that this makes it difficult to hook up WLANs to GSM networks is only just a side-effect.
Doesn't 802.11x begin to address this?
02.21.03
CANNES, France -- 3GSM Congress -- There's a big problem with connecting public wireless LAN access points to GSM/GPRS cellular networks, according to SIM card vendor SchulmbergerSema. 802.11b hotspots provide hackers with an easy way to grab user information from the wide-area network itself, the company tells Unstrung.
The heart of the problem is that when the GSM standard was being defined back in the late 80s, no one imagined that a hacker could set up his own wireless network to gain access to an operator's network and the user data therein. Therefore, GSM networks only authenticate the details held on the SIM card in a user's device before starting a session on the network. The user's device doesn't check the credentials of the network it is attempting to access.
This was fine before the advent of wireless LAN. But now for a minimal outlay anyone can own a wireless network.
At the same time, vendors and operators are starting to use SIM card-based authentication front-end systems for public wireless LAN networks, which allow them to link the user back to the home location register (HLR) database on the GSM network and thus manage and bill a subscriber on the WLAN network in the same way as they would on the wide-area network.
This all adds up to networks that could be vulnerable to hacker attacks, according to Schlumberger.
Hackers can set up "rogue" hotspots that users will access in the belief they are on the genuine public wireless LAN network. Once users are on the fake network, it is easy for the hacker to access data held on the device via the 802.11 connection (see WLAN: The Four S's and this paper for more on the insecurity of wireless LAN). Hackers can then break into the SIM software on the user's device and get the codes held there. They can then use that information to fool the GSM authentication system and thus gain access to the network.
Schlumberger say that this won't be a problem once UMTS networks are available, because the 3G standard ensures what's known as "mutual authentication" -- the network authenticates a user device, and the device confirms that it is actually on a valid network before the session can proceed.
However, for public wireless LAN implementations that will connect to backend systems on GSM and GPRS networks, Schlumberger has developed a SIM card-based system (surprise!) that enables mutual authentication between the device and networks that are accessed via the gateway of public wireless LAN hotspots. The mutual authentication takes place via algorithms on the card itself rather than in SIM card software on the device.
Schlumberger is showing a system at the 3GSM congress that uses a separate smartcard and reader plugged into a WLAN-enabled laptop. However, the firm says that the smartcard and radio could be integrated into one PCMCIA card, much in the way that Nokia Corp. (NYSE: NOK - message board) has done.
Orange France is currently testing Schlumberger's security system. Schlumberger expects that operators will start to roll it out before the end of this year.
-- Dan Jones, Senior Editor, Unstrung
http://www.unstrung.com
Ich spreche nicht wirklich Deutsch. Versuch, für eine Amerikanische Firma zu arbeiten, damit ich Amerikaner zu Ihnen sprechen kann. Dann werde ich Sie brennen. Geschäft?
With the absence of FCC police in a metropoliton area, enforcing the laws of power usage and whatnot is becomming impossible. Ofcourse you can submit a complaint but good luck having an offical actually come out and survey the damage, and while adding all of these cell phones to the mix sounds like a fun idea, its only going to cause many many problems. Why can't these hotspots be using a liscensed freq instead of publicly avaialble one? Especially now that the hams finally realised that they can use the 2.4ghz spec for data. Thats also an odd situation... The hams were way behind on the 2.4ghz issue.. they have had it available forever but was slow to catch on.. With all of these 2.4 freq. products, in a couple years we will be glowing green from all of the radiation.
Why don't we just install it under our skins and we can all be 802.11 hotspots ourselves.
- what is the definition of simultanagnosia?! I've been meaning to look it up!
In Soviet Russia, "*BSD is dying" troll is too lazy to cut'n'paste YOU!
Of course, the linked to story seems to be a 'viral' advertisement for a product that fixes this
You guys need to fact check a bit. I didn't see anywhere that mentioned that the story was under the GPL.
NO CARRIER
I am constantly being asked if wireless networks are secure.
Customer: Is this wireless networking secure?
Me: What Operating System are you running?
Customer: Windows Xpeee
Me: It doesn't matter you will never be secure.!
It is a matter of choice it can be as secure as you wish it to be. If you really think you need security tunnel through ssl..
Got Code?
Could do that inside an office, very cheap and already on lots of phones. Blue tooth hardware can be tiny in comparison to 802.11b. And covers small blackspots like in offices.
802.11b would be for bigger blackspots which begs the same question.
An Eye for an Eye will make the whole world blind - Gandhi
*BSD sucks.
Each year, the Institute for Comparative Troll Studies publishes a report on the state of trolling vis a vis national security of the United States. This year, the outlook is not good.
Although the US posesses superior trolling to Iraq, the very focus on this disparity is part of the problem. Husseins skills are perhaps at the bottom of the troll-ladder of the world. 100% votes, 'the mother of all battles', etc, are not good trolls. All they do is get him laughed at. Nobody says 'by gum, he is right'.
North Korea, however, points to a problem. North Korea 'stunned the world' by announcing it had nukes, a good troll. Unsuspected, got lots of press coverage, and caused dozens of front page articles on various magazines in the US. Even Hussein, whom the US is about to murder, has not gotten as much coverage as Kim Jong-Il. One would think the stereotype cartoonist factories have gone quiet, with the sheer lack of creativity devoted to lampooning Iraq in recent months.
North Korea is now saying that it has the right to pre-emptively attack the United States. Again, this is a pretty good troll. It simulatneously pisses people off and unbuttons their hypocrisy: the US is at the very moment trying to push forward a 'pre-emptive strike' philosophy of modern warfare: this theory has not been all that popular in the US, a nation in which children routinely justify attacks by saying 'he/she hit me first'. Again, North Korea could hardly have chosen a better subject or time to troll the world with this idiom.
But it doesn't stop there. Recently a German government official conformed to Godwin's Law and called the US leaders somewhat like Hitler. Maybe this is an urban out-of-context legend, but it doesn't matter if you are trolling, does it? The fact that it is from the same country that birthed the Nazis makes this a particularly sticky and annoying troll in the minds of the USian reader.
On the US side, we have basically been scattered. Our Trolls are lacking in quality and skill. People like Rush Limbaugh, Sean Hannity, Michael Savage, CNN, Crossfire, Bill O'Reilly, Jon Stewart, Arianna Huffington, etc, they simply do not stack up to this new breed of trolling from across the oceans.
I am not quite sure how to explain this. Perhaps the US has gotten lazy from having life too easy. Limbaugh et al are unfocused, unsure of themselves, and ignorant of the fundamentals of trolling. They lack historical background knowledge, and they fail to comprehend the motivations of the 'liberals' they tirade against. Huffington and whatnot are disconnected from the masses and unable to coalesce their vast mounds of facts about what is wrong with the conservatives into any kind of emotional climax. Their comments routinely fail to make world headlines.
American government officials like Colin Powell fail to understand trolling completely. In his simplistic view of the world, all that matters are facts and figures and slow deliberate explanation: a ludicrous proposition in any age, especially when you completely fail to produce any facts and figures to refute your most virulent opponents. Ordinarily use of facts can destroy an opponent troll, but silence never will.
His hangers on, Bush, Cheney, etc, are so completely devoid of life accomplishment or moral character (a couple DUIs, coke heads, frat boys, etc) that their lame attempts at trolling lose all credibility.
I think the US needs to implement a troll retention program, troll development and training programs, and various other troll technology that will enable it to compete in the 21st century international troll arena. Otherwise, we are just so many hot grits down the pants of history.
How do you say "*BSD users are braindead" in German?
It is amazing how much of this stuff goes on in design - if the executives of the firms involved in the standardization process can't understand the problem, it must not exist!
Every protocol out there is going to get picked apart
I am very easy to get along with, but I don't have time to waste being nice to people who are being stupid. -Theo
As thats Dutch, not German.
Interestingly, nobody in the article or here mentions the fact that there's a very active group at the IETF that's working on securing all kinds of authentication messaging systems, including EAP (the method for 802.1x wired/wireless authentication). EAP is the focus, but the papers presented at the various conferences cover many authentication methods and methods of securing them.
Protocols like EAP (Extensible Authentication Protocol) are intended to provide a generic mechanism over any transport system to handle legacy and modern handshaking and exchange to authenticate a user in a system.
In 802.1x/EAP, included as of the 802.11i wireless security update, 802.1x defines the roles of a client, access point authentication passthrough, and an authenticator. 802.1x restricts access to the network until the access point using EAP has been told by the authentication system that the client is okay to be on the network. It hands off a key, which eliminates spoofing, as even if you spoof the MAC address, you don't have the key. The key can be swapped frequently, like every 10,000 packets.
The problem with 802.1x/EAP is the same as with the SIM/GSM authentication system as described here. The authentication is sent in the clear! So you have three flavors of tunneled, SSL-like EAP: EAP-TLS (requires a pre-installed certificate on the client), EAP-TTLS (Meetinghouse, Funk support, tunnels EAP inside a tunnel), and PEAP (Microsoft, Cisco, same tunneling but ignores legacy protocols supported within EAP-TTLS).
Freelance tech journalist for the Economist, MIT Technology Review, Macworld, and others
The scenario is one where GSM operators use 802.11 to provide data-infill on their GSM networks, and reuse the GSM authentication mechanism over 802.11 to control access. The article is correct to point out that it would be relatively easy for someone to setup an 802.11 access point which pretends to belong to a GSM operator and requests GSM authentication information from connecting devices.
However, this shouldn't be too big a problem. The GSM authentication mechanism is based on a shared secret key which is written in to the SIM card in a way that SHOULD be read-only. Once its written the key is used by the SIM to calculate a response to a challenge sent from the network. This authentication algorithm is chosen by the network operator, and should be a one way function (ie you can't analyse the challenge/responses to get the secret key). Therefore, the hacker with a false network could get a set of valid responses to a set of challenges, but if the authentication algorithm is correct he can't use this data to get the secret key and clone the SIM.
The only comment I would make is that flaws have been discovered in the authentication algorithms used by some networks which potentially makes it possible to find the secret key if you have enough challenge/response data. However these algorithms are being replaced, and the computation is still quite heavy.
To summarise: fake networks attacks aren't new. Using 802.11 just makes it easier. Its best to suppress fake networks by mutual autentication, but even if you don't do this it should still be impossible for the fake network to get enough data to clone a mobile. The main problem with fake networks is that they can intercept the content of communications very easily.
They mention in the article that GSM was developed in the late 80s and then implemented around the world through out the years. It is obvious they couldn't think of all these new technologies.. progress costs something...
There will always be people that will try to break into something, so just work on ways to make it more secure.
Step 1.) Remove all Microsoft products
Someone mentioned that the authentication information for EAP is passed in the clear. EAP-SIM is not vulnerable to replay attacks because it's a challenge and response method. In normal GSM authentication, the network decides on a random challenge RAND. The network and the SIM calculate a signed response SRES and a session key Kc. The user equipment sends back SRES and the network uses it to authenticate the SIM. This leaves Kc as a shared secret at each end. EAP-SIM uses the same triplet, and uses the multiple passes for mutual authentication (theres an Internet Draft for it at http://www.ietf.org). EAP-SIM can also supply the accumulated Kc's to be used as a session key for WEP. Ok, WEP has known problems, but because you can force re-authentication periodically you can avoid a black-hat accumulating enough packets to crack your session.
BTW, Schlumberger aren't the only company offering "WLAN" SIMs - another company has been unsuccessfully lobbying 3GPP (the 3G industry standardisation body, who deal with WLAN/3G interoperation) with the same idea.
Ive done this before in a way myself.
:)
It was just an exparement at the time because I was bored.
I setup an oBSD box with wireless card in it not connected to any real network, but acting as an access point.
It handed out seemingly public IPs (It was slightly off from the real IPs my network used)
I did not use WEP on purpose, but set the network name to 'Private_GO_AWAY' (or some such message)
It then ran honeyd and pretended to be a network of a few hosts.
People looking for net access failed to get it, and most left it at that.
Once someone attempted to open a connection to any of these fake IPs, my machine portscanned them back, fingerprinted the OS, grabbed banners from any service it found running, and logged this all with date/time/MAC/hardware brand/etc info.
It also at that point started logging every packet that IP sent up until it left the wireless network.
It was fun to watch people who actually tried to 'break in' over wireless.
As i recal it was only about 5 people in a 6 month period, out of hundreds of people 'passing by' looking for net access.
Only those 5 or so people do I have detailed logs on. (I didnt bother logging anything about the ones just wanting net access, other than the fact they requested an IP and when)
If my signal is being broadcast out and they have full rights to do what they want with it, I feel the same is true for the replys from their wireless hardware to me
There is a simple solution for those that care: maintain a trusted IPSec gateway for yourself somewhere (perhaps where you keep your mail and so on) and then just use IPSec for all traffic.
Encryption makes it practical to separate the service of connectivity from the service of trust, so an untrusted hotspot can be safely used for connectivity while still maintaining a trusted connection.
here's a big problem with connecting public wireless LAN access points to GSM/GPRS cellular networks
then it goes on
802.11b hotspots provide hackers with an easy way to grab user information from the wide-area network itself, the company tells Unstrung
Now. I put a WI-FI hotspot. This WI-FI hotspot is connected to somewhere else with the internet via GSM/GPRS.
Now, How does it come that an Hacker, accessing the internet via this hotspot, can sniff the authentication details that the GPRS modem is sending to the other party? (Because this is what I understood)
The GSM Wireless network is a different protocol from the Wi-Fi. Faking a GSM Network will need that you
If I understood well, how is this related to Wi-Fi?
Or is this the problem of, "I put my pc with Wi-Fi online then hackers can access my system and if I have a GSM card then they will read what's inside?"... that's the same problem when you put yourself on a lan. If you really need Wi-Fi, you ought to put firewalls on all your Wi-Fi machines and use VPN. Or not use Wi-Fi at all...
Comments?
As was mentioned above, any network can be penetrated once physical access is obtained. Most network security is designed around the concept of trusted portions of the network; an attacker must either break through a firewall, gain control of a machine within the trusted portion of the network, or add a machine under his control to the network. Under 802.2 and related networking protocols, physical access is limited to a wire; to add a machine to the network, an attacker must at least be in the building. Under 802.11, physical access is anywhere within a certain range of a node. With the right equipment, this range can be extended considerably. Suddenly, that firewall isn't quite so effective.
My opinion hasn't changed since the first time I read about 802.11: great, useful, whatever, but NOT TO BE TRUSTED. I have an 802.11 hub on my network, but it sits in the DMZ. Wireless users around the house can still get access to the Internet and some network services, but unauthenticated machines can't get into my happy safe zone. If I needed something like that, I could set up VPN to let my wireless machines become part of the safe zone. VPN uses much better authentication and encryption than 802.11, and VPN implementations can be easily patched as the protocol improves. AFAIK, VPN authentication would defeat the attack described above.
Batou: Hey, Major... You ever hear of "human rights"? Major: I understand the concept, but I've never seen it in action
It's cynical, but not untrue.
The GSM authentication comments are not entirely true.
When the radio-connection has been established, the network sends a unique 128-bit key (RAND) to the MS (phone). The phone then uses the A3/A8 algorithm implementation, together with the RAND and an internal key stored only in the SIM (and the network's AuC) known as the Ki. This algorithm produces a 32-bit SRES (authentication check) and a 64-bit Kc (data encryption key).
RAND is sent in an AUTHENTICATION REQUEST message, and the computed SRES is sent back in an AUTHENTICATION RESPONSE. The Kc is not returned (as the network already knows it, the SRES is sent to confirm that the MS is who it says it is).
In theory, the attacker could ignore the response and begin an unciphered radio connection. However, ciphering forms an implicit form of two-way authentication. Since the Kc is used to encrypt calls, and the real Kc is not known by the network, the phone would start encrypting bursts (packets) and the network would not be able to decrypt them, hence communication would fail.
Of course, the network could simply avoid encryption by specifying no algorithm in CIPERING MODE COMMAND message, however most phones would display a warning to the user that the session is not encrypted, and hence the attack is known.
In other words, both of you are right, and I am wrong. Enjoy ;).
Thank you for your time,
Quadgoatboy
The idea that an arbitrary naive human should be able to properly use a given
tool without training or understanding is even more wrong for computing than
it is for other tools (e.g. automobiles, airplanes, guns, power saws).
-- Doug Gwyn
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