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Klarna users are being signed in to random accounts

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Re: Klarna users are being signed in to random accounts

#131
post #103
post #3

Reminds me of what happened to Steam a few years ago https://www.youtube.com/watch?v=dkSslseq9Y8

This also happened to GitHub recently, although limited. https://github.blog/2021-03-18-how-we-found-and-fixed-a-rare...

IMO this sounds more similar to the steam issue as it's probably cache related. The GitHub issue was far more subtle.

Re: Klarna users are being signed in to random accounts

#133

Their German counterpart, Sofortüberweisung, didn't properly blacklist test credentials given out by banks e.g. to developers in the beginning, so people could simply use those and pay for goods and services with fake accounts. For me there are so many red flags with all these services, as they basically "steal" your credentials to log into your online banking. And while they claim that they only use the credentials…

Can you explain more about the credentials and online banking? I've used (and integrated with) Klarna in the UK and from what I've seen it's only really a payment method with merchants who you pay back by card later.

Klarna provides many different financial services.

They provide "pay by bank account" (which involves the mentioned MITMing of users' online banking accounts, unless Klarna is integrated with your bank via OAuth/PSD2, which is still not ubiquitous), but also installment payments/factoring and others.

Re: Klarna users are being signed in to random accounts

#134
post #29

Their German counterpart, Sofortüberweisung, didn't properly blacklist test credentials given out by banks e.g. to developers in the beginning, so people could simply use those and pay for goods and services with fake accounts. For me there are so many red flags with all these services, as they basically "steal" your credentials to log into your online banking. And while they claim that they only use the credentials…

There have been some weird legal cases in Sweden where businesses and scammers have been freed after having signed in using other people's "BankID" to change retirement savings around or send cash. Its the ID method I use for credits, pharmacies, health care, taxes, but was apparently not an ID so it's not id-hijacking. Klarna has man in the middled my bank account before and performed a purchase and I've boycotting…

> There have been some weird legal cases in Sweden where businesses and scammers have been freed after having signed in using other people's "BankID" to change retirement savings around or send cash.

As far as I know most, if not all, of these scams have been perpetrated against the elderly. All operations (authentication, signing) can be initiated remotely with just a personal ID number, so the typical scam meant calling up someone and claiming that "an authentication must be performed", and simultanously initiating a bank login session. If you can keep the victim on the phone and using the BankID app when you tell them, you could basically login and empty their bank accounts. This has been largely fixed using QR codes to initiate login requests for major internet banks (which means you have to be in front of the same screen now) and other clever workarounds. But it has also always been a fact that there will be a description saying what you are signing, in the app, so being careful you could easily avoid being scammed.

I think its largely a great asset (BankID) but its never gonna be 100% tamper-proof without being seriously neutered.

Re: Klarna users are being signed in to random accounts

#135

Their German counterpart, Sofortüberweisung, didn't properly blacklist test credentials given out by banks e.g. to developers in the beginning, so people could simply use those and pay for goods and services with fake accounts. For me there are so many red flags with all these services, as they basically "steal" your credentials to log into your online banking. And while they claim that they only use the credentials…

Klarna is actually its own bank these days so that doesn't really happen anymore. I think however many other payment providers operate this way still which is ridiculous. Then again, PSD2 API roll-out has been very ???

Is that true for all European banks though? I think they all need to have an API available at this point, but is Klarna using that in every instance (instead of their legacy creepy MITM scheme) already?

Re: Klarna users are being signed in to random accounts

#136

Their German counterpart, Sofortüberweisung, didn't properly blacklist test credentials given out by banks e.g. to developers in the beginning, so people could simply use those and pay for goods and services with fake accounts. For me there are so many red flags with all these services, as they basically "steal" your credentials to log into your online banking. And while they claim that they only use the credentials…

I understand that Sofort was allowed to continue despite using the user's bank credentials because disallowing them would be anticompetitive.[0] I have no idea how that could justify such an insecure practice, but there you have it.

[0] https://knowledge.fintecsystems.com/en/blog/the-history-of-o... , under "Legal Action by Giropay"

Re: Klarna users are being signed in to random accounts

#137

I m sure it s not random but somehow systematic

Reminds me of a colleague implementing "emailRecipients" as a field in a singleton service. The first online order got an order confirmation mail, and when a second online order came s/he also got their confirmation mail (the field just grew and grew...).

Re: Klarna users are being signed in to random accounts

#139

Will be interesting to see what the problem is here. From what I have seen in real life my top guesses are. Some dependency on static variables in code. Reversed proxy with incorrect cache rules that ignores headers or some parameter.

How do you envision the static variables thing? I've seen the cache thing myself in real life but not the other.

These can act like a cache across all instances. For exactly this reason I use them only as final (constant) variables and very, very rarely mutable.

Re: Klarna users are being signed in to random accounts

#140
post #72

Sometime in the future, people will stop belittling crypto currencies when they realize that the digitization concepts of traditional finance technology providers are inferior to those of crypto currencies and blockchains. Putting safety and security first for anything that handles money makes sense. The calls for "you don't need a blockchain, just use a database" will become less and less. Edit: Of course, Hacker Ne…

This is probably the most pointless comment I have seen on HN for a long time...

Its not like BitCoin and other Coins are free of scams/fraud because they are not regulated...

Most blockchains startups need to create problems which nobody has to sell it to people who don't know better...

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