This is a valid concern with ad blockers and that they can be a target for hackers to inject a malware or switch into resources hungry miner. If you plan on using an ad blocker, it's well worth doing a bit of background research on browser extensions before installing them to be sure they have known authors and are recommended by reputable sources.
AdBlockers are the most downloaded and used add-ons on google. There is a big incentive to hack established and well-known adblocker or even to develop a new one with viruses. Until today there were already few malicious adblockers on Google downloaded more as 20 million times. This is an army of bots.
Five most known malicious adblocker add-ons already removed by Google:
- AdRemover for Google Chrome™ (10 million+ users)
- uBlock Plus (8 million+ users)
- [Fake] Adblock Pro (2 million+ users)
- HD for YouTube™ (400,000+ users)
- Webutation (30,000+ users)
Source:
https://www.techradar.com/news/google-has-kicked-five-malicious-ad-blockers-off-the-chrome-store
https://thehackernews.com/2018/04/adblocker-chrome-extention.html