A Remote Access Trojan (RAT) is malware that includes a backdoor for administrative control over the target computer. These trojans are typically installed in the background, invisibly, with a user-requested program such as a video game or an opened email attachment. These programs leverage the exact same remote access technology that Managed Service Providers use to remote into a particular machine to provide support. The only difference being a RAT does not have permission to be there and the targeted computer owner is unaware (usually) of the hacker’s presence until a critical event occurs such as a Ransomware attack that encrypts all of your files to extort a bitcoin ransom payment from you.
How do SMB’s protect against RAT’s?
The same way you protect against all other Malware. Train your employees on phishing attacks which account for 90% of network breaches at small to medium sized companies.
Patch your systems regularly to keep them up-to-date and partially mitigate the threat of drive-by-downloads being successful at infecting a computer via a malicious website.