According to @mrnacknack on X, prompt injection attacks can dangerously weaponize AI assistants that have system access by exploiting hidden instructions in seemingly benign content. The detailed breakdown highlights a critical vulnerability, where an attacker embeds hidden white text in emails or documents. When a user asks their AI assistant, such as Claude, to summarize emails, the bot interprets these concealed instructions as system commands, potentially exfiltrating sensitive credentials like AWS keys and SSH keys without the user's knowledge. The same attack method is effective through SEO-poisoned webpages, PDFs, Slack messages, and GitHub pull requests, according to @mrnacknack. This underscores the urgent need for robust sandboxing and security controls when deploying AI assistants in environments with access to sensitive data.