An email assistant is an AI tool that summarizes, drafts, prioritizes, or triages messages for a user. It sits inside the inbox workflow, so it may read untrusted content and turn it into advice or actions. That makes it useful for productivity, but also sensitive from a security perspective, because the assistant becomes part of the trust chain.
Attackers can abuse this by hiding malicious instructions inside ordinary-looking email text, a form of indirect prompt injection. The goal is not always to break the account directly; it may be to steer a summary, encourage a risky reply, impersonate a trusted coworker, or support business email compromise and fraud. Defenses include strict permission limits, mail filtering, logging, and requiring human verification for payment changes, credential requests, or executive instructions. In practice, email assistants should treat mailbox content as adversarial input, not as trusted guidance.