I came across an article written in the medium website and confirmed on ccn and twitter account of the individual.. Basically he got $100K worth of Bitcoin stolen at the time, via SIM port attack. SIM card port attack basically a type of hacking to hijack your cell phone # to a new phone, it’s not like phone # spoofing as it just change the caller ID. SIM card port hacking is still possible if you leak your personal information out such as your full name, address, DOB, social security # and secret code, personal pin etc. sadly these information can be obtained from third party database that had been previously compromised, there are programs out there that can crack the encrypted data, it’s time consuming but possible.
Now let’s talk about Bitcoin. Why would this person even store Bitcoin or anything related to Cryptocurrencies on a third party server or any exchanges for that matter. No matter how secure they are, it is always possible to crack and hack. For Cryptocurrencies it’s always best to store it on your hardware, offline storage, it will be next to impossible to get stolen or hack unless you have a gun point to your head or a fire that destroyed your hardware wallet offline wallet, but in term of hacking hardware and offline wallet, it’s not really possible. Take eobot for example they posted a 800 bitcoin address and ask hackers to go ahead and hack it, til this day 7 years later still no hackers can hack.
So the basic rule for storing your Bitcoin and other Cryptocurrencies is never ever store your coins on an Exchange or anywhere other than your own hardware wallet or offline paper wallet protected from fire and water, and off course hidden. When you need to sell your coins, simply just move it to your coinbase or where ever then execute the transaction immediately, I cannot imagine the whole process take more than 30minutes of your time. Ensure to balance $0 value at the exchange when you done.