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What went wrong at Tesco Bank?

Anonymous Coward

With cloud computing, hackers have so many more points of entry

yeah, it's an all-embracing technology :D

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WTF?

Re: With cloud computing, hackers have so many more points of entry

As opposed to online backing located in each branch????

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Big Brother

Re: With cloud computing, hackers have so many more points of entry

Your own servers you manage yourself, even if CoLo != "Cloud Computing", which is outsource to someone else's servers.

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Anonymous Coward

Re: With cloud computing, hackers have so many more points of entry

The Tesco Bank servers are not in the cloud, they are hosted in dedicated datacenters that are under Tesco control (not simply co-lo) for the most part. One of the sites is shared but the kit is in locked cages etc.

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Re: With cloud computing, hackers have so many more points of entry

"Shared" (even locked cage) is co-lo.

Not too smart for a bank but secure enough for a local Pet Shop, perhaps.

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Re: With cloud computing, hackers have so many more points of entry

You (nor me) don't know what is running on the co-lo kit and how it's secured to make an informed statement whether this is smart or not. there is plenty of insensitive data and applications in a bank that are perfectly suited for co-lo/cloud.

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Re: With cloud computing, hackers have so many more points of entry

""Shared" (even locked cage) is co-lo."

Yes, that's technically true, but it does mean random passers by cannot just get physical access to the kit, it also means no-one else is using that kit either.

How many banks are you aware of that actually *own* their own data centers? I'll give you a clue - none.

Why don't you look up who the customers are at the L3 DC on Leman street.

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Re: With cloud computing, hackers have so many more points of entry

Cloud banking 'entry points' depends.

Some of the clouds (I believe IBM's can be configured so) are essentially private fibre connections between bank HQ and dedicated servers for the really top secret data. So can really be thought of as an 'external branch network'.

Although I believe there are a range of players and options available in this field.

If the data can be anonymised and crunched offline, then returned and the data de-anonymised, cloud computing can work very well.

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Anonymous Coward

Re: With cloud computing, hackers have so many more points of entry

"If the data can be anonymised and crunched offline, then returned and the data de-anonymised, cloud computing can work very well."

One of the reasons the cloud has got where it is today is that it offers many of the long-forgotten benefits of 1960s-style timesharing - e.g. timesharing/cloud customers don't own (or control) their own resources, resources are shared with other customers and the person paying the bill has to either accept that or pay extra. Sometimes lots extra.

The approach you suggest loses the flexibility of uncontrolled sharing, and the price will doubtless reflect that. It may still make commercial sense in some circumstances.

Still, cloud == hip/trendy, What could possibly

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Santander must also not be hashing passwords

Santander online banking has a password and a PIN that you need to enter selected character/digits from - so they can't be hashing passwords either. At least they don't use email as the account identifier though.

My first direct account uses an app based 'code generator' - which doesn't seem to be TOTP/OATH. I wonder if its an established and reviewed method, or if they rolled their own solution?

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Re: Santander must also not be hashing passwords

I use Santander online and mobile app. Both request 8 digit customer ID (which you can persist for convenience) and full PIN, not selected characters from it. The mobile app won't allow you to set up new payments either and the online version sends a code via SMS you need to enter to create a new payment.

Not saying any of this is vastly secure but it sounds like Tesco have really let the security aspect slip, probably because it's difficult and a bit more expensive to deploy properly.

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Re: Santander must also not be hashing passwords

My Santander online access is a userid (can be customised) and password, which then presents you with a screen giving you a piece of information you have previously supplied to them so you can be more sure they're not a fraud site (unless it's doing some passthrough stuff) and then asks for a full 5 digit pin number.

I presume (faint hope) the banks that ask for individual character combinations from passwords / keywords have a slightly restricted list of combinations which are hashed? If my password is 10 characters long, then there are 120 different ways to choose 3 characters - it doesn't seem unrealistic to think they might have that many hashes stored for me...

Clinging to hope here!

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Trollface

Re: Santander must also not be hashing passwords

Why not just hash each character...

But more seriously, I assume the "first third and fifth" version of pin checking if for *view* only options to statements and already assured bills and payments. When ever I need to add a new bill or account to pay into, or set a new DD, I need a new pin pad check (which is hashed etc AFAIK).

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Re: Santander must also not be hashing passwords

>they can't be hashing

Well, the PIN you use for your credit/debit card payment isn't hashed either - the PIN you enter at the ATM or PoS terminal is encrypted and sent to your card-issuer where a Hardware Security Module (HSM - designed for the secure, tamper-proof storage of security credentials) checks whether it matches the PIN it contains for your account. The HSM is also used in the originating of the PIN and mailing you its value. And, indeed. there would be limited benefit in hashing a small number of characters known to be numeric.

There is no reason in principle why HSMs could not do a "masked" match for a subset of a PIN (or indeed a password), though I don't know if they're used by online banking systems in that way.

I have seem some references to the Tesco problem involving overseas debit card payments, so whether it's directly related to use of the banking website remains to be seen.

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Re: Santander must also not be hashing passwords

@ Greg 24: Both request 8 digit customer ID...

In one sense that must be "common knowledge" but you have just informed those who didn't know how long the customer ID is. In a small way you have just weakened your own security along with that of countless others.

I wouldn't tell anyone how many characters I use for any User ID and (more particularly) my passwords. Make hackers find that information out the hard way.

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Re: Santander must also not be hashing passwords

"I use Santander online and mobile app. Both request 8 digit customer ID (which you can persist for convenience) and full PIN, not selected characters from it. "

No they don't. I don't know about the mobile app, but to log in to Santander from a real computer requires the customer ID, 3 characters from your password (which actually allows strong passwords without stupid restrictive rules), and 3 digits from your 5 digit numeric PIN.

As for the main topic, this is actually an interesting problem that doesn't really have an easy solution. Only asking for a few random characters from a password is done for a very good reason - keyloggers can't steal your password if you never actually type the whole thing. But, as this incident apparently shows, this makes accounts more vulnerable to other types of attack. So the question is not so much whether it's a bad idea to do it like this, but whether it's worse than the alternatives.

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Re: Santander must also not be hashing passwords

Really? So my bank password is 15 characters. Thats 210 combinations of 'pick 2 characters'. Which is 4200 bytes of storage for the SHA-1 hashes of all of those combinations. Doesn't sound impossible to me at all.

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Anonymous Coward

Re: Santander must also not be hashing passwords

Allied Irish Bank too...

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Anonymous Coward

Re: Santander must also not be hashing passwords

NS&I asked me to give a new password over the phone the other day. (I politely declined)

This is in spite of the fact that their own website states they would never ask for one.

I currently have a complaint open on the matter - not that they seem to care.

I will be soon removing what little money I do have with them!

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Re: Santander must also not be hashing passwords

Must depend on which bank's accounts Santander historically acquired.

Our historically Alliance & Leicester login needs a numeric user ID then a five-digit PIN in full.

My business login (based on Abbey National systems) needs a numeric user ID, then a password and PIN, both in full.

Both also use the picture verification thingy, but that's pretty much entirely placebo. The user IDs are not guessable, but nor are considered secure information.

Both are now Santander branded but show their provenance in a few places. In both instances though, the password and/or PIN could be (and hopefully are) hashed.

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@jfdidave

The number of combinations can be halved, if the pair are sorted by index (i.e. if you always ask for the second and fourth characters, and never for fourth and second).

But what's the maximum allowed length of password? You have to provision for that.

And what about Natwest, who ask for four characters?

Edit: And, as some points out below, the net protection from all these hashes is far less than decent encryption.

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Re: Santander must also not be hashing passwords

Santander's login differs depending on which bank they took over that you used to be with. I locked myself out once due to their telephone banking system asking me for a field I don't have on my account.

The customer ID length being "unknown" would be very weak security by obscurity.

Storing hashes of each 3-character combination of your password (along with the necessary indexes of the characters) is pointless - it vastly reduces the attack space to brute force your password. Once you've got the first three characters, attacking another hash that re-uses 2 of your now-known characters is simple, and so on.

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Re: @jfdidave

I've just realised how trivial cracking a password stored as hashed pairs would be:

Cracking any pair by brute force is a search for a two character password.(64*64 iterations?)

Once you have at least one letter, cracking every other pair is reduced to a brute force search for a single missing character.

And if you didn't salt each pair separately, and the password contains a duplicated character, then cracking is reduced to a brute force search for a single character.

Storing hashed pairs of characters offers NO security.

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Re: Santander must also not be hashing passwords

"but to log in to Santander from a real computer requires the customer ID, 3 characters from your password (which actually allows strong passwords without stupid restrictive rules), and 3 digits from your 5 digit numeric PIN."

My current account from a 'real' computer requires me to decline installing the trusteer crap (every time because I don't keep cookies), enter a numeric customer ID, and a full numeric PIN on a page which shows a personalised icon and phrase. I seem to have a password which I am never asked and setting up a payment recipient requires more authentication.

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Re: Santander must also not be hashing passwords

Calculating and storing the hashes is not impossible at all, but if the hashed values are leaked, it's also very easy to brute-force the original password.

For each 2-character hash, you need to try less than 10,000 possible combinations of 2 characters, and you only need to brute-force 8 hashes to retrieve your 15-character password. Ouch!

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Anonymous Coward

Re: Santander must also not be hashing passwords

Actually Santander use both methods, i.e. the full length PIN or select digits depending on the legacy of your account. Newer accounts use the selected digit method.

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Re: Santander must also not be hashing passwords

"(which actually allows strong passwords without stupid restrictive rules)" This is the single most annoying thing I find when creating a password on a site.

Why is that some sites will not allow the full use of different types of characters?

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Re: Santander must also not be hashing passwords

Santander 'upgraded' (NOT!) their security. Old Santander accounts require customer ID, full passcode and full registration number. Accounts opened in the last couple of years required customer ID and three random characters from the passcode and three random characters from the registration number.

So they must be storing them using reversible encryption. and to make it look like they beefed up security they just changed the front end. No changes have gone into the way the data is stored.

What do customers do when presented with three random character shite? They chose simpler passwords don't they? No point in trying to use a 20-character random generated one when they pull this crap on you.

I don't use the Santander mobile app so can't speak for that one.

The Tesco's one is worse. The three random characters required by Santander are in fields named in the HTML as x1, x2, x3 and the three characters random are annoyingly not in order either. The Tesco's site asks for the username (not email address), full password (good) but the three random characters of the security number are presented and named as x1, x2, x3, x4, x5, x6 with the three you don't have to enter greyed out.

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Re: Santander must also not be hashing passwords

Just a shame that they're so lax on the phone. Having had them transfer several thousand pound between my accounts without any security info at all on the phone, and having had them add extra security of which the extra has never in 10 years been asked for, if you were going to do something to them, you'd just phone.

But the rest is true, they use 3 inputs from me plus a visual validation of picture and phrase I set online (edit: although it appears this isn't always the case depending on account type and vintage)

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Re: Santander must also not be hashing passwords

My ex-Abbey National account also needs a full (alphanumeric and customisable) user ID along with a password and a PIN, so that firs your theory.

I do also have it tied to a moneydashboard account too but ISTR that was set up with a one-off security exchange to prove to Santander that I wanted Moneydashboard to have read-only access to my accounts.

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Re: Santander must also not be hashing passwords

Santander UK, both business and personal versions, require a username, password, and 5 digit pin, all of which I chose. I can access my personal accounts from my business login, but not the other way round.

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Re: Santander must also not be hashing passwords

I have a cahoot account - also a Santander company. It requests 4 characters from my password and 3 of the (fixed) 5 digits of a numeric code (my choice of code).

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Gormless National Savings & investments

@ Mr ChriZ

""NS&I asked me to give a new password over the phone the other day. (I politely declined)

This is in spite of the fact that their own website states they would never ask for one.

I currently have a complaint open on the matter - not that they seem to care.

I will be soon removing what little money I do have with them!""

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Me, I **HAVE** to stick with those gormless bastards - it's the only place to put my UK Pension each month - who wants devalued Quids in a former B.C.C.

At least I might become a Millionaire before I "Snuff it".

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Re: Santander must also not be hashing passwords

"NS&I asked me to give a new password over the phone the other day"

I'm always amused at the idiocy of the banks!

I keep getting emails from my bank, inluding a "click on the link" to get to their web site.

It's like they are trying to condition their customers to become easy fishing targets!

No thanks!

I will enter the web address myself!

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Re: Gormless National Savings & investments

The only time I was ever a millionaire was in Vietnam where (at the time) there were about 30000 of the local currency to £1.

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Re: Santander must also not be hashing passwords

I wrote about 1/3 of the code for the original online banking system... expires tag (of old) was my birthday.

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Re: Santander must also not be hashing passwords

the PIN you enter at the ATM or PoS terminal is encrypted

Which is pretty pointless, given that it's included (in the clear) on the mag strip on the card..

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Re: Santander must also not be hashing passwords

The PIN is never stored on the mag stripe. You are confusing it with either the PAN (card number) or CVV.

The classic way of validating the PIN at the bank is having a HSM encrypt the PAN and then turning the first bytes of the result into digits. However, nowadays many are using a database with per-card data instead.

What is, however, occasionally stored on the mag stripe when doing it the classic way is a PIN offset to let you choose the PIN yourself - this is simply added (modulo 10 raised to the number of digits in the PIN, duh) to the encryption result to get the expected PIN. As should be pretty obvious, this value does not reveal anything about what the actual PIN is.

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Mushroom

While the details are still patchy, there's no doubt that this was a hugely sophisticated, coordinated and advanced attack

Utter tosh. Right now, we know nothing about the form the attack took. Any comment without facts to back them up is pure speculation.

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That quote is attributed to Sir Humphrey (well, maybe once removed). You need to interpret it in that context.

(And who knows what he may know that we don't?)

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"Any comment without facts to back them up is pure speculation."

Sherlock, is that you?

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Anonymous Coward

"With cloud computing, hackers have so many more points of entry"

"With cloud computing, hackers have so many more points of entry" - Sod off, absolute crock of s**t... People and Organisational culture make more of a difference to security than the platform it sits on. Odds are if you're a Project based org - i.e. get it in, once it's working, ignore it, you'll succumb to this type of attack, and in some cases, quite often. If you're more on the ball and there is a focus on operational performance (i.e. looking at what data is going out), paying for time/people to continually remediate, you'll stand a better chance of not having these instances.

Public Cloud, just like an on-premise/hosted solution will normally have it's biggest weakness in those configuring it not knowing how to configure it. That'll always leave ways in, even when done properly, they'll still be zero days. Building an architecture that is more tolerant of people mistakes, making it harder and harder for an attacker to exploit, or once exploited, get to anything meaningful is the way forward.

It's nice to see NSCS being involved here, that was only very recently setup, I'd seen their head speak at Microsoft Future Decoded, it actually looks like an organisation with the right tools/mentality for helping firms work to prevent this kind of thing happening.

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FAIL

Re: "With cloud computing, hackers have so many more points of entry"

Generally speaking I agree with the above; meatsacks, in one way or another, offer the easiest way in.

Look at that large attack on Sage recently. Although not sure how that ended up (or even if it has been announced) that smacked of an inside job with the arrest at Heathrow etc. With the Tesco bank (also based in Newcastle?) I speculated that an insider had been conned into doing something small and not realised the scale of the impact it could have. That was based on absolutely no knowledge whatsoever of banking security other than the POV of a consumer.

Then I read this article and thought what a piss weak login system for a brand new bank with no legacy code to accommodate.

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I had an email from The Co-Operative Bank a few weeks ago saying they were having to do maintenance on their banking system (long overdue!), and when I went on to my online banking I noticed now they ask for a username. If you don't have your username (which I don't) they ask you to provide your sort code and account number or the long card number. You then provide two digits from your personal pin number which I set up, then answer the question to one of 4 questions.

They then emailed roughly around the time of the Tesco hack to say their maintenance was on hold. I thought it was coincidence, but now that you mention the pin number for Tesco works the same as the Co-Op, I wonder if the underlying systems are related?

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I'm with them too

And thought the same; very coincidental.

Didn't we use to have 2FA with the Co-Op or was that just for new payments? With the card reading pin generator?

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Re: I'm with them too

There's only 2FA with the card reader when you set up a new payment method. Payments to existing payees can be made without any further checks.

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Re: I'm with them too

Those card readers for me have been a massive waste of time. They never work, I have a collection of 8 of them in my drawer.

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Re: I'm with them too

"Didn't we use to have 2FA with the Co-Op or was that just for new payments?"

Tried that. Didn't work. And as the branch in the local store (convenience of which was main reason for using them) has closed it meant an unwelcome trip into town to sort out.

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Anonymous Coward

Intersting....

The One account, Tesco Credit card and RBS also ask for random numbers and character.

All have RBS involved.

OneAccount - Originally Virgin, now owned by RBS

Tesco bank / Credit cards - Jointly set up by RBS (now run by Tesco).

Coincidence?

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Re: Intersting....

My RBS account requires the person know my STUPID account name, then a handful of password characters and part of a PIN. But to transfer any money out, add a new payee etc they'd need access to my debit card and a card reader for a challenge/response.

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