Wannacry used the exploit from EternalBlue to create one of the most famous ransomware worms in recent memory, and wasn't the only malware to leverage that one exploit: https://arstechnica.com/information-technology/2019/05/etern... https://en.wikipedia.org/wiki/WannaCry_ransomware_attack

Despite lots and lots of POCs, I haven't seen attackers use spectre in the wild yet. Maybe sophisticated actors are using it but they haven't been caught yet, or more likely they just use more traditional and reliable ways to get info leaks. But if traditional info leaks dwindle, they may turn to speculative execution attacks.