When in doubt: hang up, look up, and call back

Did a quick Google search the next day and figured the process is legit but people out there have gotten higher bills than before.

Moral is to fight the human-interaction pressures and be adamant on doing your own research. No shame in that.

The bank employee asked me to give him my passport number and acted annoyed when I refused. He couldn't understand why I would not give this kind of private information on a phone call and why it was a breach of security. I then called the bank's customer service hotline and they had no record of the call from the fraud department being made because it's a separate department and they didn't have access to that data. It took 3 days before I got a confirmation from my bank that that call had indeed been legitimate (and that's only because I have a relationship manager)...

So I think Banks are part of the problem, they need to massively step up their training in security so as not to make this kind of demands on phone calls they have themselves initiated.

Banks could normalize this behavior by having their customer service reps ask customers to do this at the beginning of every call.

"Hi, this is <csr> calling from <bank>. We'd like to talk to you about <subject>. To ensure to you that this is not a fraudulent call, please look up the phone number for this bank and call us back. Thank you."

If Verizon can't stop people from spoofing their own customer support number on their own network, we're all screwed.

The incoming message was automated, asking for (person who lives here) with a visa debit card that has fraudulent transactions. The caller id was a number not listed on the back of the card.

Pressing “1” puts you into the next phase, which asks you to “verify” your identity by - guess what - typing in your full 16 digit debit card number!

At this point I am convinced this is a scam. You google the phone number and you see tons of links saying it’s a scam.

The person calls their regular number on the back of her card and they claim no fraudulent activity.

A few days later I still get these calls so I decide to investigate. Pressing zero a bunch and asking for an agent finally gets me to a live individual. He claims they’re from pnc and they are a different section not connected to the “main” number. He’s able to recite details about the account that only pnc would know, so now I’m not sure.

I email abuse@pnc.com asking them to please either say the calls are fraudulent or acknowledge that the phone number associated with these calls is legitimate (it doesn’t appear anywhere on pnc’s web site)

I did get a response - good! But they didn’t actually change the site ... so I suppose in this case anyone who receives notification of fraud on their pnc debit card should email abuse@pnc.com to validate the calls are legitimate?

Jesus Christ. This is some Inception-level shit. I do not operate on this many levels of meta in real life.

Getting you to browse your computer for 10-20 minutes and then log into your bank account could be enough to gain access to your account.

And 2FA is proven insecure with SIM hijacking. These methods have a high up front time investment but will take even less effort than Mitch's gambit once deployed.

https://www.cs.cornell.edu/~shmat/courses/cs6431/zhuang.pdf [0]

Something about that conversation didn’t seem right, and so Mitch decided to use another phone to place a call to his bank’s customer service department — while keeping the first caller on hold.

“When the representative finally answered my call, I asked them to confirm that I was on the phone with them on the other line in the call they initiated toward me, and so the rep somehow checked and saw that there was another active call with Mitch,” he said. “But as it turned out, that other call was the attackers also talking to my bank pretending to be me.”

What happened is that the attackers made one call to Mitch, and another call to the bank posing as Mitch. When Mitch called the real bank to check up if there was a call in progress, they said yes (the call with the attackers).

I don't think I've ever had an identifiable repeat call, from which I conclude it's both effective and has a low false positive rate.

If it is about finances, YOU call them at a number on your billing statement that you know is correct, or just go to the bank.

Never make a decision / give info if "they" called you.

> “But as it turned out, that other call was the attackers also talking to my bank pretending to be me.”

I don't understand this part - the _actual_ bank said that he was on a different line with them? Wouldn't that mean that the scammers had authorised as him already, in which case the account is already compromised? Also, the bank asking for 2FA over the phone also sounds like training into bad habits, but I appreciate there's different approaches with different banks.

This is a pretty similar sequence of events to one a reasonably intelligent but non-tech friend of mine fell for this week: Got an email saying that the TV licence needed to be renewed. They followed the link on the email, didn't check the URL and filled out their account details to set up a direct debit.

Two days later, gets a call from their "bank", telling them that they filled out a scam direct debit (gets victim flustered to compromise judgement) but they need to authorise them first before they can speak any further... my friend challenged their identity but they used the exact same "fake caller ID" trick - to the correct bank number since they had the sort code from step 1, and that identifies the bank. I knew this (caller ID) was possible in general, but hadn't heard of it being actively used in the UK - only from stories in the US. After "verifying" they asked for the 2FA device code, then (registered a card for ApplePay and) asked them to "confirm" the code they had just been texted, which is the point I walked in and was "WTF are you doing?"

About 10 minutes later while in the waiting queue for the actual bank, the actual bank called them - when we said that we wouldn't trust the call they instantly gave us a reference number to quickly recall the case and advised us to call back quickly. Luckily, the bank reimbursed the amounts taken before they locked it off (apparently some UK agreement from a couple of years ago.)

They were pretty shaken up from the experience, and want to know what to look for in the future. It strikes me that a lot of these cases are hitting otherwise reasonably cautious people who aren't aware that something they think is authentication, really isn't, like caller ID.

1. If someone who calls you asks you for ANY sensitive personal info, just tell them that your policy is to not give any personal info to those who called you, but you’re happy to call the official number. That stops it right there

2. Use email aliases instead of your actual email when creating accounts with eg Amazon Web Services. An email alias is like me+somethinghere@gmail.com — this way the attacker can’t get the customer service rep to give them access to your account easily.

3. If you use your phone as a 2FA, be on the lookout for sim porting - that’s when they trick the rep into porting your phone number.

I had the third one happen, luckily I acted fast. The attackers couldn’t get into my G Suite email but they got into godaddy to port the domain and MX records to their servers. So they could receive email sent to me, and send email as me. They also changed my GoDaddy password. I had my phone as the 2FA at the time. Better to not have one at all, or use an authenticator app.

I called in and luckily GoDaddy restored my account. Too bad they had no tool to check what changed so I had to check every domain manually.

The attacker was too slow in that regard. But it was telling that I received an email with the subject “Test”. That’s what tipped me off.

I feel like if we ran a public education campaign about how easy it is to spoof caller ID, a lot of these scams would stop working, but that's probably just me being foolishly optimistic.

Basically, the scammer would instruct a suspicious mark to hang up, look up their bank's phone number, and call back, just as Krebs is instructing. As soon as the mark hung up, the scammer would begin playing a dial tone instead of hanging up. When the mark picked up the phone, they would hear the dial tone, so they would begin dialing at which point the scammer would end the dial tone, wait for the dialing to stop, and then play a few ring tones and then pretend to pick up the phone. This was in the 90s so the technology was there to automate it, but it's simple enough it could have been done completely manually by stopping and starting recordings. From the user's perspective, it seemed they had hung up and made a call to the bank, so it seemed impossible that they were connected to someone else.

Cell phones, which don't stay connected when only one party hangs up, are totally immune to this hack. And this hack has probably fallen out of use since the ubiquity of cell phones has deprived scammers of a viable pool of marks.

Another simple trick used by the fraudsters is to ask the called parties to hang up and dial their bank, but after the victim hangs up, the fraudster does not, keeping the line open and remaining connected when the victim picks up the phone to dial.[4] When in doubt, calling a company's telephone number listed on billing statements or other official sources is recommended, as opposed to calling numbers received from messages or callers of dubious authenticity. However, sometimes hanging up and redialing is insufficient: if the caller has not hung up, the victim might still be connected, and the fraudster spoofs a dial tone down the phone line to entice the victim to dial. Then the fraudster's accomplice answers and impersonates whomever the victim is trying to call.[5] This is known as a 'no hang-up' scam.[6] Hence consumers are advised to use a different phone when dialing a company's number to confirm.

When in doubt: hang up, look up, and call back "from a different number".

Funny enough, I never got a call back from canada revenue agency for, being less than polite to them, and the spam calls stopped.

My advice, if you actually get a real person on the line, call them out on their shit and tell them to fuck off. It seems to work.

Whoa, a double-tap attack

My response is not picking up the phone at all.

When you are starting a new person to person transaction with an unknown party, it seems impossible to verify that an attack like this is not happening. The attacks could get arbitrarily complex and every defense I can think of has repucussions.

Even trying to start a transaction could be replayed to someone to make it look like I was the one that was doing the scamming.

Wow. In the UK as far as i'm aware no bank uses auth codes over txt, we have a physical devices to generate one time codes for identification or transaction signing using chip and pin.

Most people here are aware txt messaging is not secure, it's enough of an issue for email hijacking, I'm very surprised banks are using it in US.

Imho, this is where the phone company should be liable. If I let people masquerade as other users in my software, it would be a critical security bug and I'd be in deep trouble. But we just accept this crap from phone companies.

Later on I called back, to verify that it was someone from the bank who had phoned me.

The call-centre person in the bank who answered my call was unable to confirm or deny if someone from the transaction-checking department had actually phoned me, because it was all very confidential.

We need verified identity for phone numbers and email, with consequences attached to bad behaviour.

Page 126 (page 10 of the PDF) from RJA’s Security Engineering being my reference...

https://www.cl.cam.ac.uk/~rja14/Papers/SEv3-ch4-dec18.pdf

If, in retrospect, you feel someone was attempting to scam you, a better option - I hope - might be to contact the bank's fraud line, explain that you are suspicious, and have them look for suspicious activity.

For how often you need that kind of cash readily accessible it's simply not worth the risk for the overwhelming majority of people.

This was a really sophisticated attack and fooled even a security conscious person but defense in depth (not having the big bucks accessible from your general use card and/or following up on unknown transactions) would have stymied it. With a good security protocol breaking one rule (not hanging up and calling back) shouldn't screw you.

This is our password & credentials, now please confirm your identity.

If someone really wants your stuff, they are going to get it.

The cost of getting this guy's money was very high relative to the average scam - but it's important to note that the cost of sophisticated multi-factored scams is dropping.

How is it possible for someone not to check his/her bank account all this time? There were unknown transactions for several weeks and no one noticed?

IMHO not having alerts for your cards/accounts and not noticing strange transactions is a bigger security risk than trusting the telephone number calling you.

I fully agree that we should call back on the official number for any banking issues and don’t blindly trust whoever is pretending to be from the bank.