One of the many reasons I selected Supabase/PGvector for RAG is that the vectors and their linked content are stored with row level security. RLS for RAG is one of PGvector's most underrated features.
Here's how it mitagates a similar attack...
File Upload Protection with PGvector and RLS:
Access Control for Files: RLS can be applied to tables storing file metadata or file contents, ensuring that users can only access files they have permission to see.
Secure File Storage: Files can be stored as binary data in PGvector, with RLS policies controlling access to these binary columns.
Metadata Filtering: RLS can filter file metadata based on user roles, channels, or other security contexts, preventing unauthorized users from even knowing about files they shouldn't access.
How this helps mitigate the described attack:
Preventing Unauthorized File Access: The file injection attack mentioned in the original post relies on malicious content in uploaded files being accessible to the LLM. With RLS, even if a malicious file is uploaded, it would only be accessible to users with the appropriate permissions.
Limiting Attack Surface: By restricting file access based on user permissions, the potential for an attacker to inject malicious prompts via file uploads is significantly reduced.
Granular Control: Administrators can set up RLS policies to ensure that files from private channels are only accessible to members of those channels, mirroring Slack's channel-based permissions.
Additional Benefits in the Context of LLM Security:
Data Segmentation: RLS allows for effective segmentation of data, which can help in creating separate, security-bounded contexts for LLM operations.
Query Filtering: When the LLM queries the database for file content, RLS ensures it only receives data the current user is allowed to access, reducing the risk of data leakage.
Audit Trail: PGvector can log access attempts, providing an audit trail that could help detect unusual patterns or potential attack attempts.
Remaining Limitations:
Application Layer Vulnerabilities: RLS doesn't prevent misuse of data at the application layer. If the LLM has legitimate access to both the file content and malicious prompts, it could still potentially combine them in unintended ways.
Prompt Injection: While RLS limits what data the LLM can access, it doesn't prevent prompt injection attacks within the scope of accessible data.
User Behavior: RLS can't prevent users from clicking on malicious links or voluntarily sharing sensitive information.
How it could be part of a larger solution:
While PGvector with RLS isn't a complete solution, it could be part of a multi-layered security approach:
Use RLS to ensure strict data access controls at the database level.
Implement additional security measures at the application layer to sanitize inputs and outputs.
Use separate LLM instances for different security contexts, each with limited data access.
Implement strict content policies and input validation for file uploads.
Use AI security tools designed to detect and prevent prompt injection attacks.