Comment by zacksiri | Hacker News Reader

Comment by zacksiri | Hacker News Reader

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Usually the cases show up on social media in our country. The victims post that they’ve been frauded and generally blame it on the banks.

The banks then reply and say “the fraud transaction originated from customer’s device”. When you look at the screenshots of victims giving example it’s all Android as far as I can see.

Generally after talking to the banks and customers discover that it was their own fault for clicking on a seemingly harmless link they shut up and go quiet.

This is a story that plays out often here.

I don’t particularly have a link because these cases get deleted from social media (by the customer themselves) after the bank has proven that it’s the customers fault.

Edit: You can try searching the internet for “mobile banking fraud Thailand” you’ll find these links, here is one example.

https://www.bangkokpost.com/business/2524469/mobile-banking-...

Edit: here is an example the article mentions downloading of .apk on android

https://www.nationthailand.com/thailand/general/40024972

Can't the banks implement some measures so that only their own apps can do transactions?

Believe me they’re trying. They’re now mandating biometric authentication, and I don’t mean on device, I mean implemented by the banks app / backend. If you read the articles you’ll see.

Each year the central banks up the ante on security protocols to implement to stop the fraud. I should know I used to work for a finance app here in Thailand.

We have to go through strict security audits, and procedures that costs a lot for any financial institution to implement.

Doing 2 FA is already a mandate for doing transactions. However 2FA in Thailand is mostly done using SMS which is still not that secure.

Forcing everyone to use a token or a 1Password app is also not viable since that’s going to shut a lot of people out of mobile banking.

It’s a complex problem, which I think Apple has already solved. Disabling sideloading reduces so much costs downstream and made things simple and secure for the lay man.

Literally nothing that you've said is a good excuse for forbidding sideloading. It would be actually trivial for a bank to only allow transactions from their apps, if they can't do that then they should be forced to take responsibility for fraud.

Guess what happens currently on iOS instead? Instead of installing a custom app, you are sent a link to log in to a dodgy bank page with all your details with the exact same result.

>>Disabling sideloading reduces so much costs downstream and made things simple and secure for the lay man.

I don't believe this is the case, and I really believe any arguments otherwise are made in bad faith to maintain the status quo because obviously apple could never do any wrong.

> It would be actually trivial for a bank to only allow transactions from their apps

How?

What do you mean how? The app has a secure token only the app has, any traffic without that token is invalid. IOS already sandboxes all apps so the token would be impossible to extract. This is basic app security, I can't believe this is even discussed

> The app has a secure token only the app has

What kind of token? How does it obtain it?

This is how I think it roughly works where I live: You get a per-user token directly at the bank or via mail (not email, but a physical envelope). Your banking app can use this token once to get a secret key. Secret key + user name + password allows you to use the banking app.

Any way to circumvent this requires app isolation to be broken somehow.

Sadly, there’s a far more straightforward way. The phisher says “Sorry, your token has expired! You will need to get a new one…” Plenty of people will fall for it.

Also, I wouldn’t personally describe an out-of-band token delivery / exchange mechanism like that as “actually trivial” for apps to do.

People extract tokens from apps all the time. Jailbreaks for modern versions of iOS do exist and if they become too hard to pull off, that'll just create a market for pre-jailbroken devices.

Tokens embedded into your app can and will be extracted. You can make life harder for criminals by rapidly updating tokens and invalidating all but the last X updates, but I doubt your users are going to like that, and I doubt criminals will be stopped for long with the amount of money at stake.

There are ways to make it incredibly difficult for hacked apps but if the file ends up at a user's device, you lose control.

I'm not following. So we have to keep to the locked app store-only model because if we allowed sideloading....people could jailbreak their devices and apps could extract secrets? I don't follow.

>>that'll just create a market for pre-jailbroken devices.

I don't understand - people will get pre-jailbroken devices so they can be hacked easier? The whole idea with forcing apple to allow sideloading is that you can be on the very latest, most secure iOS version and sideload apps.

I think you misunderstand. The secure token you mention isn't secure if it's part of your app, like any other API key or password. Fake apps will just extract that token from the real app and insert it into their own code.

And how exactly will they do that on a non-jailbroken fully updated iOS installation?

Not to mention that iOS apps keep those kinds of secrets in the Secure Enclave and you can't get anything out of it unless you are the app that put the secret in there in the first place - that doesn't change whether apple allows sideloading or not. If you need a jailbreak to break that protection then this isn't something that will affect your "normal" user like many here are worried about. Normal iOS protections will be more than enough.

> And how exactly will they do that on a non-jailbroken fully updated iOS installation?

This is irrelevant because banks need to support people using older versions of iOS as well.

> Not to mention that iOS apps keep those kinds of secrets in the Secure Enclave

iOS doesn’t store tokens in the Secure Enclave. It can generate keys and use them to sign things, but keys and tokens are different things. The Secure Enclave isn’t a generic secret store, it has very specific, limited functionality. Are you perhaps mixing it up with the keychain?

Also, you didn’t answer the question:

> What kind of token? How does it obtain it?

It’s still unclear whether you are thinking of a static token bundled with the application or a per-user token obtained during first use. In the former case attackers can just download the IPA and extract it themselves without even thinking about attacking a user’s device. In the latter case, you need a mechanism to distribute tokens to untrusted devices, so that is the most likely entry point for an attack, not trying to obtain an existing token after the fact.

I hate that baks require the phone app, where transactions don’t also require a computer: It enables racket where my aggressor can list my bank accounts; It also reduces the 2FA to 1FA (phone-only transactions with password + fingerprint + SMS only on the phone).

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