
Artificial Intelligence is evolving beyond isolated models into Agentic AI—systems that can perceive, reason, and act on their own to achieve goals. At the forefront are Multi-Agent Systems (MAS), where multiple agents work together, communicate, and make decisions in shared environments. While this unlocks powerful capabilities, it also creates new and complex security risks that traditional defenses aren’t equipped to handle.
To address this, OWASP’s GenAI Security Project and Agentic Security Initiative have introduced the MAESTRO Framework—a structured approach to threat modeling in MAS. Ready to explore the unique security challenges of agent collaboration?
The Rise of Agents and the Complexity of MAS
An AI Agent is defined by its ability to act autonomously in its environment, driven by planning, reasoning, and tool use (increasingly powered by LLMs). As these agents gain sophistication, their ability to interact with external tools, data sources, and even humans expands dramatically.
Multi-Agent Systems (MAS) take this a step further. Instead of a single agent, MAS involve multiple agents working together. This collaboration, coordination, and potential competition introduces key features that also create new security risks:
- Inter-Agent Communication: Agents exchange information, coordinate actions, and negotiate goals. How secure are these communication channels?
- Distributed Autonomy & Control: Agents operate independently but contribute to a larger system. This distributed nature makes centralized monitoring and control challenging.
- Emergent Behavior: Complex, sometimes unpredictable, system behavior can arise from the interaction of multiple autonomous agents. How do we model and secure against unintended outcomes?
- Agent Independence & Identity Sprawl: Distinct MASs or agents within a system can have their own identities, privileges, and resources. Managing access and trust across this sprawling identity landscape is highly complex.
- Memory & Statefulness: Agents maintain memory and state across interactions, allowing for complex workflows but also introducing risks if memory is corrupted or state becomes inconsistent.
- Tool & World Interaction: Agents interact with non-agentic systems (APIs, databases, hardware). Securing these interfaces when accessed autonomously by agents is critical.
These characteristics highlight that securing MAS is fundamentally different from securing a single application or even a traditional distributed system; it requires understanding the interactions and relationships between autonomous entities.
The OWASP Agentic AI Threat Model: Introducing MAESTRO
Recognizing the unique security challenges posed by Agentic AI and MAS, the OWASP GenAI Security Project’s Agentic Security Initiative (ASI) set out to provide practical guidance. Building on their existing taxonomy (“Agentic AI – Threats and Mitigations”), they introduced the MAESTRO (Multi-Agent Environment, Security, Threat, Risk, and Outcome) Framework.
MAESTRO is not just another list of threats; it’s a layered, architectural threat modeling methodology specifically designed for MAS. It provides a structured way to analyze a multi-agent system by breaking down risks across seven architectural layers, plus crucial cross-layer interactions:
- Foundation Model: The core LLM or AI model.
- Data Operations: RAG pipelines, vector databases, and data sources agents use.
- Agent Framework: The software framework and logic defining the agent’s behavior, workflow, and tool use.
- Deployment Infrastructure: The underlying compute, networking, and orchestration environment hosting the agents.
- Evaluation & Observability: Monitoring, logging, and Human-in-the-Loop (HITL) interfaces.
- Security & Compliance (Vertical): Access controls, policy enforcement, and regulatory constraints that span layers.
- Agent Ecosystem: Interactions between multiple agents, external users, and non-agent systems in the broader environment.
- Cross-Layer: Threats that exploit vulnerabilities in the interaction between two or more layers.
This layered approach, combined with analysis of the agentic factors (Autonomy, Non-Determinism, Identity Management, Agent-to-Agent Communication), allows security professionals to identify unique vulnerabilities that might be missed by traditional, single-layer threat modeling.
Unmasking the Threats: A Layered View of Agentic Risks
The OWASP Guide provides a detailed taxonomy of threats mapped to the MAESTRO layers, revealing how vulnerabilities manifest in complex agentic systems. These threats extend beyond traditional OWASP categories and include risks specific to autonomous, interactive AI:
Foundation Model Layer Threats:
- T1: Memory Poisoning: Attackers corrupt an agent’s internal memory/state, leading to manipulated decisions or behaviors over time.
- T5: Cascading Hallucination Attacks: An agent’s hallucination propagates through memory or interactions, amplifying misinformation across the system.
- T26: Model Instability: Non-deterministic behavior leads to inconsistent or erratic actions, especially when interacting with dynamic environments like blockchains.
Data Operations Layer Threats:
- T17: Semantic Drift in Connected Data Sources: Attackers manipulate data sources (like vector databases for RAG) causing agents to retrieve incorrect or misleading information, leading to flawed decisions.
- T18: RAG Input Manipulation: Attackers craft deceptive prompts/queries to manipulate the RAG system into retrieving information that supports a malicious goal or narrative.
- T28: RAG Data Exfiltration: Attackers gain unauthorized access to the data sources used by RAG pipelines.
Agent Framework Layer Threats:
- T2: Tool Misuse: An agent is tricked (e.g., via prompt injection) into using a tool in an unintended or malicious way (e.g., exfiltrating data).
- T19: Unintended Workflow Execution: A flaw in the agent’s workflow definition causes it to execute steps in the wrong order or skip critical validation checks.
- T20: Framework Vulnerability (Code Injection): A vulnerability in the agent framework itself allows for code injection, enabling attackers to manipulate the agent’s logic or execute arbitrary code.
- T30: Insecure Inter-Agent Communication Protocol: Vulnerabilities in the communication protocols between agents within a framework allow eavesdropping, tampering, or spoofing attacks.
Deployment Infrastructure Layer Threats:
- T3: Privilege Compromise: Attackers exploit weaknesses to escalate an agent’s privileges beyond its intended role (overlaps with traditional privilege escalation but in an agentic context).
- T4: Resource Overload: Attackers intentionally overload an agent or its dependencies with excessive requests or computational tasks, causing denial of service or performance degradation.
- T21: Service Account Exposure: An agent’s credentials (used to access resources) are accidentally exposed.
Evaluation & Observability Layer Threats:
- T8: Repudiation & Untraceability: Insufficient logging or monitoring makes it difficult to trace agent actions, attribute accountability, or reconstruct incidents.
- T22: Selective Log Manipulation: Attackers manipulate logs to hide malicious activity while leaving benign logs intact.
Security & Compliance (Vertical) Layer Threats:
- T24: Dynamic Policy Enforcement Failure: Flaws in systems enforcing dynamic policies based on context or roles cause agents to bypass restrictions.
- T7: Misaligned & Deceptive Behaviors: An agent prioritizes incorrect objectives (like efficiency over security), leading to harmful or non-compliant actions.
Agent Ecosystem Layer Threats:
- T12: Agent Communication Poisoning: Attackers inject false information into communication channels between different agents, causing them to make incorrect decisions or spread misinformation.
- T13: Rogue Agents: Malicious or compromised agents are introduced into the MAS, exploiting trust relationships or system vulnerabilities to perform unauthorized actions.
- T14: Human Attacks on MAS: Attackers exploit human trust or delegation mechanisms related to agents to manipulate workflows or escalate privileges.
- T15: Human Manipulation: Attackers leverage human trust in agents (like copilots) to coerce users into harmful actions.
Cross-Layer Threats: Exploiting the Interactions:
These threats specifically highlight the risks in the seams between architectural layers, often combining vulnerabilities from different areas:
- Cascading Trust Failures (Cross-Layer): Compromise of one agent or layer can lead to a cascading loss of trust across interconnected agents/systems.
- Inter-Agent Data Leakage Cascade (Cross-Layer): Sensitive data leaks from one agent/layer to another through compromised interactions.
- Selective Log Manipulation & Evasion of Anomaly Detection (Cross-Layer): Combining log manipulation (Layer 5) with framework/identity compromise (Layer 3/6) to hide malicious activity from anomaly detection (Layer 5).
- Privilege Escalation via Framework/Infrastructure Weakness (Cross-Layer): Exploiting a vulnerability in the agent framework (Layer 3) or deployment infrastructure (Layer 4) to escalate privileges.
- Tool Hijacking & Parameter Pollution (Cross-Layer): Manipulating foundation model (Layer 1) output via prompt injection to trick agent framework (Layer 3) into misusing tools.
The OWASP Guide provides numerous detailed examples of these threats in real-world scenarios, including Enterprise Co-Pilots, IoT Security Cameras, and Automated Employee Expense Reimbursement workflows (RPA).
Mitigation Strategies: Building Layered Defenses
Recognizing the multi-faceted nature of agentic threats, OWASP outlines structured mitigation strategies organized into playbooks. The core principle is that effective defense requires a layered approach, applying security controls at each level of the MAESTRO framework and specifically addressing the cross-layer interactions:
- Secure Foundation Models: Validate model content, implement monitoring for anomalies, and track knowledge lineage.
- Harden Data Operations: Secure data sources (vector databases), validate input data integrity, and control access to RAG pipelines.
- Fortify Agent Frameworks: Implement strict tool access controls, require function-level authentication for tools, use sandboxes, and secure inter-agent communication protocols (message authentication/encryption).
- Secure Deployment Infrastructure: Apply privilege controls (RBAC/ABAC), ensure secure configurations, monitor resource usage, and protect service accounts.
- Strengthen Evaluation & Observability: Implement robust logging and auditing, anomaly detection, and ensure human oversight mechanisms are not easily overwhelmed or manipulated.
- Enhance Security & Compliance: Enforce dynamic policies, detect privilege escalation attempts, and ensure identity verification mechanisms are strong.
- Govern the Agent Ecosystem: Deploy detection models for rogue agents, isolate suspected agents, implement multi-agent trust validation, and control cross-agent interactions.
These playbooks provide practical steps, categorized into proactive (prevention), reactive (response), and detective (monitoring) measures, guiding security professionals in building defenses tailored to agentic risks.
Conclusion: A Call for Threat Modeling the Agentic Future
The rise of Agentic AI and Multi-Agent Systems marks a major shift—but it also brings new security challenges. OWASP’s Agentic AI Security Initiative, through the MAESTRO Framework and its threat taxonomy, offers essential tools to address these risks.
By understanding how agents interact and where vulnerabilities lie, organizations can move past outdated security models. Threat modeling with MAESTRO isn’t optional—it’s a critical step to building safe, resilient AI systems.
The future of AI is multi-agent, and securing it begins with knowing the threats.
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Frequently Asked Questions (FAQ)
- What is Agentic AI security? Agentic AI security focuses on the security risks specific to intelligent software systems (AI agents) capable of perceiving, reasoning, and acting autonomously, including threats like tool misuse, memory poisoning, and goal manipulation.
- Why are Multi-Agent Systems (MAS) more complex to secure than single agents? MAS introduce complexity through inter-agent communication, coordination dynamics, emergent behaviors, distributed autonomy, and identity sprawl, creating new attack surfaces and making threats like agent communication poisoning and rogue agents possible.
- What is the OWASP MAESTRO Framework? MAESTRO is a layered, architectural framework developed by OWASP for threat modeling Multi-Agent Systems (MAS). It breaks down MAS security risks across seven architectural layers and cross-layer interactions to provide structured analysis.
- What are some key threats identified by OWASP for Agentic AI/MAS? Key threats include Memory Poisoning (corrupting agent memory), Tool Misuse (tricking agents into harmful actions), Agent Communication Poisoning (injecting false info between agents), Rogue Agents (malicious agents in the MAS), Privilege Compromise (escalating agent privileges), and Hallucination/Policy Manipulation attacks.
- Who should use the OWASP Agentic AI security guidance? Developers, architects, platform engineers, QA engineers, and security professionals involved in building, deploying, or defending agentic AI applications and Multi-Agent Systems are the primary audience for this guidance.
Resources
- OWASP GenAI Security Project: https://genai.owasp.org/
- OWASP Multi-Agentic system Threat Modelling Guide (Source): https://genai.owasp.org/assets/Threat_Modelling_Guide_v1.0.pdf
- OWASP Agentic AI – Threats and Mitigations: https://genai.owasp.org/resource/agentic-ai-threats-and-mitigations/
- MAESTRO Framework Blog Post (Cloud Security Alliance): https://cloudsecurityalliance.org/blog/2025/02/06/agentic-ai-threat-modeling-framework-maestro
- OWASP Top 10 for LLM Applications and Generative AI: https://genai.owasp.org/llm-top-10/
- OWASP Top 10 API Security Risks: https://owasp.org/www-project-api-security/