I had about 0.02 bitcoins in my wallet for couple of years, but when I've started bitcoin wallet last time I've found out three transactions (two incoming and one outgoing), which I've never authorized:
4/1/18 18:51 Confirmed (2508 confirmations). Sent to (no label) 18wrbpmkwNTCyT6BYNYEenzRXKvf8ZXHHc -1.97508779 4/1/18 18:43 Confirmed (2509 confirmations). Received with (no label) 1HMpg6iHbwWmeezxfczKPH5ZK5NCTx5n5x 1.19001290 4/1/18 18:13 Confirmed (2510 confirmations). Received with (no label) 1HMpg6iHbwWmeezxfczKPH5ZK5NCTx5n5x 0.76083845
I can't fully rule out that somehow I've lost my wallet key. Although it was a local wallet on my PC in a Bitcoin Core client. And PC wasn't even on on that day. But then, they would have just transferred the money out and that's it. But here it seems to be some kind of attack, by first sending money, then cancelling transactions and getting them back with high transaction fee. It doesn't fall under any bitcoin weakness described on this page. So I'd be glad if someone help me understand what has happened.