From Mother Jones:
If Russian hackers have done this, it implies that Russia may have information on Donald Trump's organization that could compromise his duties as US president.
Four years ago, the Trump Organization experienced a major cyber breach that could have allowed the perpetrator (or perpetrators) to mount malware attacks from the company’s web domains and may have enabled the intruders to gain access to the company’s computer network. Up until this week, this penetration had gone undetected by President Donald Trump’s company, according to several internet security researchers.
If Russian hackers have done this, it implies that Russia may have information on Donald Trump's organization that could compromise his duties as US president.
Another computer security expert, who also asked not to be named, notes that this network of shadow subdomains may have been established by a criminal enterprise looking to use the Trump Organization’s computer system as the launching pad for various cyberattacks on other individuals or entities. But, he adds, this breach also could be exploited by state or nonstate actors attempting to infiltrate the Trump Organization. “At the least,” he remarks, “it shows the Trump Organization has been badly run.”