Security of check account/routing numbers

[Halfsmoke]

@doug2

account numbers and routing numbers - which are printed on the checks! How crazy is that?

@Shamino

But it is quite surprising that there hasn’t been massive check fraud
[…]
I assume the banks employ anti-fraud technologies that don’t involve knowledge of account numbers, but I don’t know what they might be.

@jeff1

As I understand it, ACH transactions are protected by the ability to revoke them when you can, for example, show the signature was forged. Credit cards work similarly if your card is hacked. This may cost the bank/credit card money, but it seems to work well enough for them.

Some related points:

1. Checks have account information printed on them because they are remmants of a legacy money transfer method that was designed decades ago. There isn’t much motivation for banks to modernize paper checks because checks are used less and less and less every year plus, perhaps most importantly, the risk of fraud is entirely borne by the acceptor of a check, not their bank.
2. Another, mercenary, reason banks don’t change paper checks is that many generate fee income from bad checks.
3. ACH transfers can be reversed, but the conditions vary by bank and type of transaction. Also, requests must be made in a very short time frame (often hours, not weeks as is the case with credit card disputes).
4. Wire transfers are pretty much irreversible.
5. Credit card disputes in the US are governed by very specific federal regulations. This means banks can and do handle disputed ACH and other money transfer transactions differently from disputed credit card transactions.