according to different observation i think few ways are available for abusing bitcoins transections such as Technical weakness , Greedy peoples ro dishonest people , proper management. i would like to describe above mentioned quotatin in briefly
1. technical weakness: we know its a peer to peer transection system throgh confirmed way. within a few second a dishonest person can get more money by fast clicking when submit second payment of different recipient.
2. proper management: there is so many lack of proper management of human or account holders. so many hackers want to hack system for getting money because bitcoins holder don't have any insurance like bank account holders. even government don't follow rules and regulation for virtual currency holders.
So what you think about it ?
Pretty confused about your first point, I'm guessing you're referring to a bug being exploited on a third party site or something like double spend which isn't possible in every case.
Regarding your second point, the Bitcoin system is foolproof and can almost be called hack resistant, at least till the 2030 as told by cryptography experts. The only way that any sorts of losses could be incurred due to hacks would be on fragile third party sites offering exchange/wallet services.
Even the cryptography experts said that by 2030; only the supercomputers will even be able to achieve that but we may just have to wait until then. I am not sure even the Tianhe-2 can even achieve that for now.
Moreover, one thing I am sure of is that a lot of changes will always be made in technologies that would really make it hard for even some of these new devices to be able to achieve this and I believe bitcoin devs would not even sit and relax to let that happen.