Attackers followed the tools: phishing that looks like an AI assistant, malicious browser plugins, and staff pasting secrets into public chats. For a small firm the threat is rarely exotic; it is routine habit.

SME AI security is three bright red lines: finance machines stay off public AI tools, customer data never enters a public prompt, and every browser plugin needs approval before install.

One training session is not enough. A short monthly drill — spotting fake assistant emails and the rule “never paste credentials” — often beats buying an expensive security product the team will ignore.

If you use closed APIs, keep keys in a password manager and scope access by role; most leaks start in a chat file or a screenshot.

Manager action: Block public AI domains on accounts/finance machines; train staff never to paste credentials.