Trojan.StolenData is Malwarebytes’ generic detection name for files, folders, and registry entries with user data gathered by other Trojans.
Even though Trojan.StolenData is not malware itself, the presence of it on a system indicates that there has been a data theft. Stolen data is usually stored encrypted on the users’ machines, and it is hard to find out what exactly was stolen.
Malwarebytes protects users from Trojan.StolenData by using real-time protection to stop the trojans that gather stolen data.
Malwarebytes can detect and remove Trojan.StolenData without further user interaction.
Since the presence of this Trojan indicates that data was stolen, you should act accordingly. Change your passwords. Use a password manager if you weren’t using one, so it’s no hassle to use a different and complex password for all accounts. Also be aware of spear phishing attempts and other attempts to defraud you using the stolen data.