#Card Security | Explore Tumblr posts and blogs

mostlysignssomeportents · 9 months ago

Text

How I got scammed

If you'd like an essay-formatted version of this post to read or share, here's a link to it on pluralistic.net, my surveillance-free, ad-free, tracker-free blog:

https://pluralistic.net/2024/02/05/cyber-dunning-kruger/#swiss-cheese-security

I wuz robbed.

More specifically, I was tricked by a phone-phisher pretending to be from my bank, and he convinced me to hand over my credit-card number, then did $8,000+ worth of fraud with it before I figured out what happened. And then he tried to do it again, a week later!

Here's what happened. Over the Christmas holiday, I traveled to New Orleans. The day we landed, I hit a Chase ATM in the French Quarter for some cash, but the machine declined the transaction. Later in the day, we passed a little credit-union's ATM and I used that one instead (I bank with a one-branch credit union and generally there's no fee to use another CU's ATM).

A couple days later, I got a call from my credit union. It was a weekend, during the holiday, and the guy who called was obviously working for my little CU's after-hours fraud contractor. I'd dealt with these folks before – they service a ton of little credit unions, and generally the call quality isn't great and the staff will often make mistakes like mispronouncing my credit union's name.

That's what happened here – the guy was on a terrible VOIP line and I had to ask him to readjust his mic before I could even understand him. He mispronounced my bank's name and then asked if I'd attempted to spend $1,000 at an Apple Store in NYC that day. No, I said, and groaned inwardly. What a pain in the ass. Obviously, I'd had my ATM card skimmed – either at the Chase ATM (maybe that was why the transaction failed), or at the other credit union's ATM (it had been a very cheap looking system).

I told the guy to block my card and we started going through the tedious business of running through recent transactions, verifying my identity, and so on. It dragged on and on. These were my last hours in New Orleans, and I'd left my family at home and gone out to see some of the pre-Mardi Gras krewe celebrations and get a muffalata, and I could tell that I was going to run out of time before I finished talking to this guy.

"Look," I said, "you've got all my details, you've frozen the card. I gotta go home and meet my family and head to the airport. I'll call you back on the after-hours number once I'm through security, all right?"

He was frustrated, but that was his problem. I hung up, got my sandwich, went to the airport, and we checked in. It was total chaos: an Alaska Air 737 Max had just lost its door-plug in mid-air and every Max in every airline's fleet had been grounded, so the check in was crammed with people trying to rebook. We got through to the gate and I sat down to call the CU's after-hours line. The person on the other end told me that she could only handle lost and stolen cards, not fraud, and given that I'd already frozen the card, I should just drop by the branch on Monday to get a new card.

We flew home, and later the next day, I logged into my account and made a list of all the fraudulent transactions and printed them out, and on Monday morning, I drove to the bank to deal with all the paperwork. The folks at the CU were even more pissed than I was. The fraud that run up to more than $8,000, and if Visa refused to take it out of the merchants where the card had been used, my little credit union would have to eat the loss.

I agreed and commiserated. I also pointed out that their outsource, after-hours fraud center bore some blame here: I'd canceled the card on Saturday but most of the fraud had taken place on Sunday. Something had gone wrong.

One cool thing about banking at a tiny credit-union is that you end up talking to people who have actual authority, responsibility and agency. It turned out the the woman who was processing my fraud paperwork was a VP, and she decided to look into it. A few minutes later she came back and told me that the fraud center had no record of having called me on Saturday.

"That was the fraudster," she said.

Oh, shit. I frantically rewound my conversation, trying to figure out if this could possibly be true. I hadn't given him anything apart from some very anodyne info, like what city I live in (which is in my Wikipedia entry), my date of birth (ditto), and the last four digits of my card.

Wait a sec.

He hadn't asked for the last four digits. He'd asked for the last seven digits. At the time, I'd found that very frustrating, but now – "The first nine digits are the same for every card you issue, right?" I asked the VP.

I'd given him my entire card number.

Goddammit.

The thing is, I know a lot about fraud. I'm writing an entire series of novels about this kind of scam:

https://us.macmillan.com/books/9781250865878/thebezzle

And most summers, I go to Defcon, and I always go to the "social engineering" competitions where an audience listens as a hacker in a soundproof booth cold-calls merchants (with the owner's permission) and tries to con whoever answers the phone into giving up important information.

But I'd been conned.

Now look, I knew I could be conned. I'd been conned before, 13 years ago, by a Twitter worm that successfully phished out of my password via DM:

https://locusmag.com/2010/05/cory-doctorow-persistence-pays-parasites/

That scam had required a miracle of timing. It started the day before, when I'd reset my phone to factory defaults and reinstalled all my apps. That same day, I'd published two big online features that a lot of people were talking about. The next morning, we were late getting out of the house, so by the time my wife and I dropped the kid at daycare and went to the coffee shop, it had a long line. Rather than wait in line with me, my wife sat down to read a newspaper, and so I pulled out my phone and found a Twitter DM from a friend asking "is this you?" with a URL.

Assuming this was something to do with those articles I'd published the day before, I clicked the link and got prompted for my Twitter login again. This had been happening all day because I'd done that mobile reinstall the day before and all my stored passwords had been wiped. I entered it but the page timed out. By that time, the coffees were ready. We sat and chatted for a bit, then went our own ways.

I was on my way to the office when I checked my phone again. I had a whole string of DMs from other friends. Each one read "is this you?" and had a URL.

Oh, shit, I'd been phished.

If I hadn't reinstalled my mobile OS the day before. If I hadn't published a pair of big articles the day before. If we hadn't been late getting out the door. If we had been a little more late getting out the door (so that I'd have seen the multiple DMs, which would have tipped me off).

There's a name for this in security circles: "Swiss-cheese security." Imagine multiple slices of Swiss cheese all stacked up, the holes in one slice blocked by the slice below it. All the slices move around and every now and again, a hole opens up that goes all the way through the stack. Zap!

The fraudster who tricked me out of my credit card number had Swiss cheese security on his side. Yes, he spoofed my bank's caller ID, but that wouldn't have been enough to fool me if I hadn't been on vacation, having just used a pair of dodgy ATMs, in a hurry and distracted. If the 737 Max disaster hadn't happened that day and I'd had more time at the gate, I'd have called my bank back. If my bank didn't use a slightly crappy outsource/out-of-hours fraud center that I'd already had sub-par experiences with. If, if, if.

The next Friday night, at 5:30PM, the fraudster called me back, pretending to be the bank's after-hours center. He told me my card had been compromised again. But: I hadn't removed my card from my wallet since I'd had it replaced. Also, it was half an hour after the bank closed for the long weekend, a very fraud-friendly time. And when I told him I'd call him back and asked for the after-hours fraud number, he got very threatening and warned me that because I'd now been notified about the fraud that any losses the bank suffered after I hung up the phone without completing the fraud protocol would be billed to me. I hung up on him. He called me back immediately. I hung up on him again and put my phone into do-not-disturb.

The following Tuesday, I called my bank and spoke to their head of risk-management. I went through everything I'd figured out about the fraudsters, and she told me that credit unions across America were being hit by this scam, by fraudsters who somehow knew CU customers' phone numbers and names, and which CU they banked at. This was key: my phone number is a reasonably well-kept secret. You can get it by spending money with Equifax or another nonconsensual doxing giant, but you can't just google it or get it at any of the free services. The fact that the fraudsters knew where I banked, knew my name, and had my phone number had really caused me to let down my guard.

The risk management person and I talked about how the credit union could mitigate this attack: for example, by better-training the after-hours card-loss staff to be on the alert for calls from people who had been contacted about supposed card fraud. We also went through the confusing phone-menu that had funneled me to the wrong department when I called in, and worked through alternate wording for the menu system that would be clearer (this is the best part about banking with a small CU – you can talk directly to the responsible person and have a productive discussion!). I even convinced her to buy a ticket to next summer's Defcon to attend the social engineering competitions.

There's a leak somewhere in the CU systems' supply chain. Maybe it's Zelle, or the small number of corresponding banks that CUs rely on for SWIFT transaction forwarding. Maybe it's even those after-hours fraud/card-loss centers. But all across the USA, CU customers are getting calls with spoofed caller IDs from fraudsters who know their registered phone numbers and where they bank.

I've been mulling this over for most of a month now, and one thing has really been eating at me: the way that AI is going to make this kind of problem much worse.

Not because AI is going to commit fraud, though.

One of the truest things I know about AI is: "we're nowhere near a place where bots can steal your job, we're certainly at the point where your boss can be suckered into firing you and replacing you with a bot that fails at doing your job":

https://pluralistic.net/2024/01/15/passive-income-brainworms/#four-hour-work-week

I trusted this fraudster specifically because I knew that the outsource, out-of-hours contractors my bank uses have crummy headsets, don't know how to pronounce my bank's name, and have long-ass, tedious, and pointless standardized questionnaires they run through when taking fraud reports. All of this created cover for the fraudster, whose plausibility was enhanced by the rough edges in his pitch - they didn't raise red flags.

As this kind of fraud reporting and fraud contacting is increasingly outsourced to AI, bank customers will be conditioned to dealing with semi-automated systems that make stupid mistakes, force you to repeat yourself, ask you questions they should already know the answers to, and so on. In other words, AI will groom bank customers to be phishing victims.

This is a mistake the finance sector keeps making. 15 years ago, Ben Laurie excoriated the UK banks for their "Verified By Visa" system, which validated credit card transactions by taking users to a third party site and requiring them to re-enter parts of their password there:

https://web.archive.org/web/20090331094020/http://www.links.org/?p=591

This is exactly how a phishing attack works. As Laurie pointed out, this was the banks training their customers to be phished.

I came close to getting phished again today, as it happens. I got back from Berlin on Friday and my suitcase was damaged in transit. I've been dealing with the airline, which means I've really been dealing with their third-party, outsource luggage-damage service. They have a terrible website, their emails are incoherent, and they officiously demand the same information over and over again.

This morning, I got a scam email asking me for more information to complete my damaged luggage claim. It was a terrible email, from a noreply@ email address, and it was vague, officious, and dishearteningly bureaucratic. For just a moment, my finger hovered over the phishing link, and then I looked a little closer.

On any other day, it wouldn't have had a chance. Today – right after I had my luggage wrecked, while I'm still jetlagged, and after days of dealing with my airline's terrible outsource partner – it almost worked.

So much fraud is a Swiss-cheese attack, and while companies can't close all the holes, they can stop creating new ones.

Meanwhile, I'll continue to post about it whenever I get scammed. I find the inner workings of scams to be fascinating, and it's also important to remind people that everyone is vulnerable sometimes, and scammers are willing to try endless variations until an attack lands at just the right place, at just the right time, in just the right way. If you think you can't get scammed, that makes you especially vulnerable:

https://pluralistic.net/2023/02/24/passive-income/#swiss-cheese-security

Image: Cryteria (modified) https://commons.wikimedia.org/wiki/File:HAL9000.svg

CC BY 3.0 https://creativecommons.org/licenses/by/3.0/deed.en

#pluralistic #social engineering #phishing #ai #swiss cheese security #infosec #finance #fraud #carding

10K notes · View notes