There are 3 really simple things you can do to protect yourself against 90% of social engineering attempts. Most of these operations are casting a big net and just trying to scoop up unsuspecting fish. So make yourself a slightly harder target and they will pass right over you. 1. Don’t ever answer the phone for unknown numbers. Even when the location says Mountain View, CA, or the caller ID says Google. It’s fake! To ensure you don’t get tricked, set your phone setting to Silence unknown numbers automatically. On iPhone it’s Settings ➡️ Phone ➡️ Screen Unknown Callers ➡️ Silence (see screenshot). Many times, bad actors are using fear over the phone to get you to do things you shouldn't - like give them control of your email. 2. Add 2FA to your main email account, and make sure it uses a unique, strong password. Use either an authenticator app or a Yubikey (better) as your 2FA. Accounts.google.com ➡️ Security & sign-in ➡️ Turn on 2-step verification. Then make sure your password is a unique password that isn't used anywhere else. If you are using the same password in more than one place, it's highly likely that it's been leaked. Just go to haveibeenpwned.com, put in your email address, and look at how many leaks its been in. 3. If you use Google Authenticator, turn off the cloud sync. When you have cloud sync on, if someone compromises your Google account, they can steal your 2FA. It makes 2FA ➡️ 1FA, and that is bad. These are the basics that you can do to protect yourself against a huge amount of social engineering. And then if you want extra protection for your BTC, check out the next post 👇

What a mess. Unfortunately this Trezor address leak will directly lead to an increase in targeted social engineering and potentially wrench attacks. Here are my recommendations for what to do if you were in this breach (or just want to protect yourself against the result of these breaches in the future). Social engineering protection Scammers will use the combination of having your personal information to both target you (phone, email) and convince you that they are legit (using your name and potentially home address as proof that they know you and are here to help). They will contact you via phone or email with targeted lies meant to scare you into talking to them and taking the actions they want you to, in the name of protecting your bitcoin. Ignore any communication from "Trezor" that doesn't come from their official domains (the @Trezor handle, trezor.io are the main ones I know of). You should also ignore communication from "Google" or "Apple" pretending like your email is compromised. They trick you into giving them your email credentials, and then once inside your inbox they can do all manner of things to trick you without Google's typical filters stopping them. Generally a company's support team will never call you on the phone without you contacting them. If they reach out proactively and are trying to get you to take any action to "remain safe" - refuse. Social engineers steal much more money on a regular basis than physical attackers. Most people worry about physical attack more because it sounds scarier, but the bigger risk of actual funds loss is social engineering. Get your suspicion antennae up. Phishing Phishing has a lot of overlap with social engineering. The main difference in my mind is that phishers put in less effort than social engineers. Social engineers may use phishing tools to help them. Phishers are just putting their nets out and trying to get you to make a mistake. Be very suspicious of emails directing you to go to Trezor's website or download a new Trezor app. Triple check the URL for Trezor or any hardware wallet website that you visit. Even if you Google Trezor, there are fake Trezor phishing apps running Google ads that will tell you to type in your seed phrase and then steal your money. Be very careful when downloading or using new wallet apps that you are getting the right one. Wrench attacks The one everyone worries about the most, even though it's the least common. Unfortunately since this breach includes physical addresses, it's possible we will see some wrench attack attempts come from it. Unless you are going to move, the best you can do is try to deter attackers and make sure that if it happens, they can't steal all your money. Distribute your keys and use a multisig to ensure that you don't have enough keys to spend bitcoin at your house. Then consider keeping a small-ish amount of BTC in a single sig wallet that you are willing to give up to make someone go away. We don't recommend the type of duress wallet that uses the same device/software as your main wallet, but when you type in a different PIN it brings up the fake wallet. It's too hard to remember the duress PIN when someone is beating you up, and too easy to give in when they ask you for more after you pay them from the duress wallet. You need to make it so you truly can't send them all your money. Casa recently built Guardian Mode to help protect against social engineering and wrench attacks. It requires the Casa key to sign for all transactions you send. We do a video verification call to make sure you are not being tricked or under duress before signing with our key. Available to Premium+ Casa members. You can also check out an old post we did about physical home security, which unfortunately we have to reshare every year or two: blog.casa.io/a-home-defense-… Very sorry to all the people who were caught up in this. Rough few weeks for bitcoin security. Reach out to us if you need assistance on any of these points.

The onchain metrics around the Coldcard incident reinforce how important self custody is to the resilience of Bitcoin as an asset class. In the couple of days around the hack: - 2.1k BTC was stolen - 22k moved to exchanges - 233k moved out of long term holder wallets in on chain transactions We at Casa know (based on actual customer conversations) some of the 233k was people moving from non-Coldcard single sig (ie Ledger, Trezor) to multisig wallets, because they realized single sig wasn’t secure enough for their needs. And other coins were moved from multisig->multisig as people removed Coldcard from their keyset. So somewhere between ~10x-100x the amount of bitcoin stolen was moved to safety as people sounded the alarm. This is a giant flashing neon sign showcasing the resilience that self custody adds to the network. If all that BTC was held at a custodian and the custodian was hacked instead, those numbers would have been flipped. A little bit might have gotten out the door to safety, and most would be stolen. As it was, the thieves had to crack one wallet at a time (and are still going), earning a little BTC each wallet, instead of cracking one wallet and getting a massive payday. And the asset price (and confidence) would have certainly taken a much bigger hit. Self custody is not just good for Bitcoiners, it is good for Bitcoin. H/t to @_Checkmatey_, @intangiblecoins, @SaniExp for the data