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Phishers Defeat Citibank's 2-Factor Authentication
An anonymous reader writes "Crypto experts and U.S. Government regulations (FFIEC) have been pushing the need for financial Web sites to move beyond mere passwords and implement so-called "two-factor authentication" — the second factor being something the user has in their physical possession like a token — as the answer to protecting customers from phishing attacks that use phony e-mails and bogus Web sites to trick users into forking over their personal and financial data. According to a Washington Post Blog, 'SecurityFix,' phishers have now started phishing for the two-factor token ID from the user as well. The most interesting part is that these tokens only give you one minute to log in to the bank until that key will expire. The phishers employ a man-in-the-middle attack against the victim and Citibank to log in via php and conduct money transfers immediately when logged in." (An update to the blog entry notes that the phishing site mentioned has since been shut down.)
My bank has had this for ages. How's about protecting you from the man in the middle attack by a little extra procedure, though ? Immediately after you've done the transactions through the web and you log out, the bank sends you an encrypted email with all your transactions in it. Those emails can be parseable for your own financial package as well. And it should give you some time to cancel all the transactions that are bogus. There can be no forgery involved, since the bank _always_ sends those mails. Just an idea, I know there's no cure for utter stupidity.
Religion is what happens when nature strikes and groupthink goes wrong.
My bank (Rabobank, netherlands) uses a key-generating hardware device, based on account, PIN number, optional numbers generated by the site (which are to be entered into the keygen) and an internal clock. With sending any transfer, the site requires a new key to be generated. If the amount to be transferred is sufficiently large, one of the numbers used to generated the key is the exact amount, thus requiring the user to validate the amount as well.
Phishers may be able to coordinate up to the point of this validation, but if one suddenly had to enter an additional verification number of, e.g. "2000.00" (minus the decimal point), it'd be very hard to use phishing for large amounts of money.
Then again, I also have other accounts at two other banks, both of which require only a one-time, 5/6-digit, non-changing, numeric password.
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Nearly all US and UK Internet banking systems are susceptible to this.
There is an easy fix for this as well - client side certificates. I have an account with a bank in an ex-eastern European country and they use it. Many scandinavian banks use that as well (with the certificate on a token or a smartcard).
In order to authenticate the SSL handshake has to use both client side and server side certificates. After that the actual user id has to match the certificate one. A man in the middle cannot break through that because it will not have the private key from the user machine. From there on even if it can fake the bank interface to the user it cannot fake the user towards the bank. Game, set and match.
The only reason for US and UK banks not to use it is outright incompetence. I remember trying to explain the concept of client side SSL certificates to one of the cretins who have implemented a well known UK bank Internet banking security subsystem. He could not grasp the concept. By the way - he now works in the "risk" (that is the way they like calling this now) department of another well known UK bank.
Baker's Law: Misery no longer loves company. Nowadays it insists on it
http://www.sigsegv.cx/
But in this case simple and common SSL certificate verification would work to stop such a man-in-the-middle attack.
SSL (and other such certification systems) present a trust problem:
When I connect to Alice, she presents a certificate which is signed by Bob. This tells me that Bob has verified that Alice is who she says she is. All very good you might think... except why the hell should I trust Bob? Maybe "Alice" is really Charlie pretending to be Alice and Bob signed the certificate because Charlie paid him a whole heap of cash. Or maybe Bob just didn't actually bother to check before signing the certificate. Either way, I don't know Bob and so he hasn't earnt my trust.
In this case, Bob is someone like Verisign - a large corporation who has been paid a reasonably large amount of money by Alice. If there's one thing I've learnt it's that most large corporations are fundamentally untrustworthy, especially when they're receiving bundles of cash from someone.
This kind of trust problem is not easilly solvable (if it's actually solvable at all). One potential way to do things is have a social network - each person signs the certificates of each of their friends and assigns a "trust score" showing how strong their trust relationship is. When I want to see how trustworthy Alice is, I traverse the network if signatures between me and Alice and can calculate the end "trustworthyness" from the scores of all the interconnections in the network. The problem here is that there usually aren't that many hops between any 2 people in the network - I might trust Bob and Bob might trust Alice, even though *I* don't trust Alice.
http://blog.nexusuk.org
I know this won't fix all problems with phishing emails, but it should fix one factor of it. Could those who contribute their programming skills to Firefox make it so the actual domain of the site you are at is highlighted? This means that if you are at a site
http://citibusinessonline.da.us.citibank.com.tufel -club.ru/sahdlhasal
Firefox would display it as:
http://citibusinessonline.da.us.citibank.com. tufel-club.ru /sahdlhasal
I know some victims refuse to think about it at all and refuse to even look at the URL but this would give them one more tool to use to possibly see it is a scam.
But why is the rum gone?
A primary reason for the difference between US security standards and European security standards is the compute environment, and hence, the assumption of trust given to the terminal.
In the US, most users are accessing their accounts from their work or home computers. Although keyloggers may be present on these machines, it isn't very common yet. In northern europe, the use of internet terminals in cafes or kiosks is much more common. On these machines, it is likely that keyloggers will be present, so it is conservative to assume that everything the user does will be logged someone.
This assumption (everything the user does is logged) drives the need to require access to some thing (PIN grid, token generator, etc) that is needed in addition to the normal username and password. The higher level of justified paranoia drives a higher perception of security requirements.
One tremendous downside to this: loss of one of the best features of online banking - ease of use and portability. I personally have about ten online accounts with different banks, and I use all those accounts frequently. Everything I need to know to manage my personaly finances is carried in my head, and I can access my accounts from any computer anywhere in the world with nothing more than the knowledge I possess. Having to carry any sort of physical object to access my accounts would be a tremendous loss, one that would probably drive me to seek another bank, or a bank in another country, to avoid.