Threat model
What are we trying to defend?
VecShield examines privacy and security risks in vector stores and the retrieval layer, including sensitive personal data, regulatory obligations and attacks on stored knowledge.
Privacy: personal data in vector stores
Personal data can remain in stored chunks and metadata after source documents are embedded, making it available to retrieval even when teams do not know it is there. VecShield detects personally identifiable information (PII) in vector-store content and maps observations to applicable regulatory frameworks, including GDPR and CCPA / CPRA. It also detects protected health information (PHI) and cardholder data, with mappings to HIPAA and PCI-DSS respectively.
Findings identify the sensitive-data categories observed, the obligations that may apply and the evidence needed for review. Values are masked by default, and coverage distinguishes scanned, sampled and unscanned content. Detection and framework mapping support privacy and compliance decisions; they are not legal determinations or guarantees of compliance.
Poisoning
Anyone who can influence a document that gets ingested can influence what the model later reads. The instruction or false claim is stored with the content, so it does not need to be typed into the application. VecShield looks for prompt-injection text in stored chunks, chunks with no recorded provenance, and embeddings that are anomalous for their collection. A match is an indicator for a reviewer, not proof that content is malicious.
Attacker-controlled content
RAG ingestion
Poisoned knowledge base
Malicious / incorrect retrieval
LLM
Data leakage
Permissions on source documents often do not follow chunks into the vector store, and an application usually queries with one service credential. VecShield probes whether one tenant or namespace can retrieve another's data, scans stored chunks and metadata for personal, health, payment and credential data, and audits API keys for excess or stale privileges.
Tenant A query
One tenant's request
Vector store
Shared collection
Tenant B chunk
Cross-tenant data exposure
Collection extraction
A client that can query the store can often recover much of its content by asking many related questions. With query monitoring enabled, VecShield flags bulk reads, enumeration attempts and collection-wide retrieval patterns. It does not sit between your application and the store.
Repeated semantic queries
Progressive recovery
Content collected across queries
Stored knowledge
Collection contents extracted
Scope
VecShield covers privacy and security at the retrieval and vector-store layer, including regulation-based sensitive-data detection. It is not a generic LLM jailbreak detector.
Not covered
- Generic LLM jailbreak detection or prompt filtering at the chat interface.
- Model training-data extraction, model theft or weights security.
- Vulnerabilities in your application code outside the retrieval path.
- Legal determinations. Findings are evidence for a human reviewer.
References
- OWASP Top 10 for LLM Applications 2025: LLM08 Vector and Embedding Weaknesses
- Greshake et al., Not what you've signed up for: Compromising real-world LLM-integrated applications with indirect prompt injection (arXiv:2302.12173)
- Zou et al., PoisonedRAG: Knowledge corruption attacks to retrieval-augmented generation (arXiv:2402.07867)
- MITRE ATLAS