I just read this news about how a Ukrainian hacker group stole more than $50 million in bitcoin by running some AdWords campaigns Here. According to the news, hackers created some phishing website for popular bitcoin wallets, then run AdWords campaigns on popular cryptocurrency(bitcoin) related keywords misleading innocent visitors who have searched for those keywords to their malicious websites which were mirrored with actual websites.
I don't want to copy and paste all the content here. So please refer the Original Source: http://blog.talosintelligence.com/2018/02/coinhoarder.html for more detailed information.
Cisco has been tracking a bitcoin theft campaign for over 6 months. The campaign was discovered internally and researched with the aid of an intelligence sharing partnership with Ukraine Cyberpolice. The campaign was very simple and after initial setup, the attackers needed only to continue purchasing Google AdWords to ensure a steady stream of victims. This campaign targeted specific geographic regions and allowed the attackers to amass millions in revenue through the theft of cryptocurrency from victims. This campaign demonstrates just how lucrative these sorts of malicious attacks can be for cybercriminals. Additionally, the revenue generated by these sorts of attacks, can then be reinvested into other cybercriminal operations.