My sites just got hacked in SiteGround with the same hack. Whateve Siteground says about their advanced security is simply false advertisement. They couldn’t stop it on the perimeter with all their ‘advertised intrusion detection systems and ModSecurty rules’ and their official response in support was ‘it is your problem’.
So I wouldn’t go s far as saying that their security is excellent. It is as bad as any other hosting out there, they just make a lot of false promises.