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SQL patterns I use to catch transaction fraud

analytics.fixelsmith.com

101–110 of 138 posts

Re: SQL patterns I use to catch transaction fraud

#101

This is AI slop, as has been pointed out by several other commenters. Flagged.

side topic: why should AI slop be banned or eschewed when 80% of the articles on here are ABOUT AI? In other words, why is HN so keen on promoting the pseudo-science of making AI work, then recoil when presented the fruits of their own labor? Seems contradictory and elitist. Like trying to force the board of McD's to Mukbang 3+ happy meals each.

Re: SQL patterns I use to catch transaction fraud

#102
These all seem pretty elementary TBH. they focus on identifying fraudulent transactions, vs (IME) the more valuable deciding if a transaction is fraudulent. This is totally double today. Example: instead of some sort of "outside of normal transaction" you can confidently determine that "coffee at 2am" is likely fine, if they also bought gas 10 minutes earlier from the same merchant, dinner 300 miles away at 7pm, and again gas 8 hours ago in their home town.

Re: SQL patterns I use to catch transaction fraud

#103
post #2

> Real cardholders almost never buy something for exactly $1.00. Coffee is $4.73, gas is $52.81. The roundness is the signal. Surely this depends on how the vendor sets their prices? If you're going to buy something from a website to test a stolen credit card you don't just get to make up your own prices. And I think you may be over-indexing on the US "prices don't include tax" thing. Elsewhere, round-number prices a…

I do not know if this is still used anywhere, but in the past there were places, e.g. hotels or car rental services, where the validity of a credit card was tested by a $1.00 transaction, before booking a room or renting a car.

In North America they typically charge a much bigger deposit for these with a hold unit after everything clears. This makes sense; it's more important that you have the credit than just a functioning CC, but doesn't really help with fraud.

Re: SQL patterns I use to catch transaction fraud

#104
post #2

> Real cardholders almost never buy something for exactly $1.00. Coffee is $4.73, gas is $52.81. The roundness is the signal. Surely this depends on how the vendor sets their prices? If you're going to buy something from a website to test a stolen credit card you don't just get to make up your own prices. And I think you may be over-indexing on the US "prices don't include tax" thing. Elsewhere, round-number prices a…

This is also a) trivial to bypass by adding dither to the test transactions and b) trivial to improve upon with proper statistical analysis and c) shouldn't this kind of heuristic pattern recognition with no expectation of near-100% accuracy be what AI is good at?

> a) trivial to bypass by adding dither to the test transactions and

I know someone who worked in fraud detection of financial transactions. He told me that indeed lots of filters that are applied mostly test for anomalies. The thing is that most criminals are not insanely smart, and commonly don't have a lot of inside knowledge about accounting, banking, finance system etc., so criminals often have a bad intuition about more subtle things that are looked at for fraud detection.

But if you are a very dedicated criminal with lots of inside knowledge about, say, accounting, banking, finance system, ..., you could likely outsmart these filters. But these people typically have much better career options (even if they want a career as a "big fish criminal": just look at the history of accounting scandals, stock manipulations, Ponzi schemes, ...).

Re: SQL patterns I use to catch transaction fraud

#105

Earlier quoted context omitted.

I'm seeing a few stores here and there which have a "round up to donate" option. I guess I'm a bit of a sucker and I always use that option. My groceries are always a round number as a result.

Ive always suspected that this is all of a tax dodge, a money spinner, and a pr exercise "we gave xxx to charity" - no, your customers did. Just set up a direct debit to your favourite charity.

Agree - I don't think a giant multinational should get the cumulative charitable donation through their "Gavin Belson Foundation", and frankly it coming while you're checking yourself out, and navigating all dark-pattern "share your email for an e-receipt?", "want our deal of the day?", "enter your loyalty card?", "fill out this poll?", "are you collectioning stickers?" nonsense really grinds my gears. I just want cheaper groceries!

Re: SQL patterns I use to catch transaction fraud

#106

This is AI slop, as has been pointed out by several other commenters. Flagged.

side topic: why should AI slop be banned or eschewed when 80% of the articles on here are ABOUT AI? In other words, why is HN so keen on promoting the pseudo-science of making AI work, then recoil when presented the fruits of their own labor? Seems contradictory and elitist. Like trying to force the board of McD's to Mukbang 3+ happy meals each.

AI != slop. Just because I'm positive about AI doesn't mean I want to consume slop. I personally use AI for productive means, not to write and publish low-quality articles.

Re: SQL patterns I use to catch transaction fraud

#108

Earlier quoted context omitted.

side topic: why should AI slop be banned or eschewed when 80% of the articles on here are ABOUT AI? In other words, why is HN so keen on promoting the pseudo-science of making AI work, then recoil when presented the fruits of their own labor? Seems contradictory and elitist. Like trying to force the board of McD's to Mukbang 3+ happy meals each.

AI != slop. Just because I'm positive about AI doesn't mean I want to consume slop. I personally use AI for productive means, not to write and publish low-quality articles.

pushing slop is "productive means" for many people. they can sell the accounts/identities to election-manipulators or advertisers. bots age like fine wine.

Re: SQL patterns I use to catch transaction fraud

#109

Earlier quoted context omitted.

AI != slop. Just because I'm positive about AI doesn't mean I want to consume slop. I personally use AI for productive means, not to write and publish low-quality articles.

pushing slop is "productive means" for many people. they can sell the accounts/identities to election-manipulators or advertisers. bots age like fine wine.

So what? They can do whatever they want, that still doesn't mean we need to allow these posts.

Re: SQL patterns I use to catch transaction fraud

#110
I agree the post looks a little AI written but generally this kind of analysis is quite common. Leaving aside human heuristics that are generally too well known to catch real scammers (like time travel or "7 days", which is bad because often weekly patterns are important so at the very least look at 10 days) and actually have low precision, what I find odd it that all results just return a user ID.

So this is really just surfacing cases, but with not enough context to be useful to prioritise. I would expect a score to be included.

Apart from that it misses a lot of signals like refunds, declines, disputes etc [1].

1) https://stripe.com/gb/guides/improve-fraud-management-with-r...

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