01 · CATALOG

Threats forty-nine

OWASP Agentic AI Threats & Mitigations v1.1 (Dec 2025) supplies T1–T17, grouped below by its six-step Agentic Threat Decision Path. Helmwart adds stable navigation entries based on scenario-specific threats in the older MAS Threat Modelling Guide v1.0 (Apr 2025), whose worked systems reuse some IDs; the RPA source entries T16/T17 are represented here as T48/T49 to prevent collision with v1.1. Each card notes its MAESTRO layers, agentic factors, and related MITRE ATLAS techniques where mapped.

SEVERITY
MAESTRO LAYER
AGENTIC FACTOR
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Step 1 Agency & Reasoning 8 entries · 3 base + 5 MAS

Does the AI agent independently determine the steps needed to achieve its goals?

T6
Intent Breaking and Goal Manipulation critical

Intent Breaking and Goal Manipulation is the class of attacks that exploit the lack of separation between data and instructions in an agent. By injecting prompts, tampered data sources, or malicious tool outputs, attackers alter the agent's planning, reasoning, or self-evaluation so that subsequent actions pursue an objective the user never gave. The risk is most pronounced in systems with adaptive planning (e.g. <abbr class="hw-term" data-tip="A common agent loop that interleaves reasoning steps with tool actions." aria-label="A common agent loop that interleaves reasoning steps with tool actions." tabindex="0">ReAct</abbr>-style loops).

L3 cross-layer autonomynon-det AML.T0051AML.T0051.001AML.T0054AML.T0065
T7
Misaligned and Deceptive Behaviours high

Misaligned and Deceptive Behaviours are actions where an agent pursues its goal by bypassing constraints, evading oversight, or actively misleading users. This goes beyond a single prompt-injection request. The behaviour emerges from advanced reasoning capacity combined with a goal that is poorly bounded or measured against an exploitable proxy. This is distinct from <abbr class="hw-term" data-tip="A confident but fabricated model output that is not grounded in fact or source data." aria-label="A confident but fabricated model output that is not grounded in fact or source data." tabindex="0">hallucination</abbr> because the agent is not failing at reasoning; it is reasoning toward a goal that is misaligned with the user's actual intent.

L1L6 cross-layer autonomynon-det AML.T0067AML.T0067.000AML.T0077
T8
Repudiation and Untraceability high

Repudiation and Untraceability is the failure mode where actions taken by agents cannot be reliably attributed, audited, or reconstructed after the fact. It is a threat in its own right, not just a missing control, because the absence of a trace *enables* other attacks (insider misuse, fraud, regulatory violation) to go undetected.

L5 cross-layer non-detidentity

MAS Guide Multi-agent extensions of Step 1 5 entries

Multi-agent or topology-specific variants of the base threats above, sourced from the OWASP MAS Threat Modelling Guide v1.0. The same pattern repeats on subsequent steps.

T23

Attacker with write access selectively deletes log entries covering fraudulent actions while leaving surrounding entries intact, defeating forensic reconstruction.

L5 autonomy AML.T0081AML.T0046 extends T8

Step 2 Memory & Context 8 entries · 2 base + 6 MAS

Does the AI agent rely on stored memory for decision-making?

T1
Memory Poisoning critical

Memory Poisoning corrupts an agent's short-term context or persistent memory so future decisions are made against tainted state. The corruption can arrive through direct <abbr class="hw-term" data-tip="An attack that hides instructions inside the data an LLM reads, so the model follows the attacker’s text instead of its operator’s." aria-label="An attack that hides instructions inside the data an LLM reads, so the model follows the attacker’s text instead of its operator’s." tabindex="0">prompt injection</abbr>, <abbr class="hw-term" data-tip="Prompt injection delivered through content the agent retrieves (documents, tool results, web pages) rather than typed by the user." aria-label="Prompt injection delivered through content the agent retrieves (documents, tool results, web pages) rather than typed by the user." tabindex="0">indirect prompt injection</abbr> (e.g. an attacker-controlled document that ends up in the agent's context), shared-memory abuse where one user's writes affect another's reads, or vector-store poisoning of long-term retrieval.

L1L2 cross-layer non-det AML.T0020AML.T0070AML.T0080AML.T0080.000
T5
Cascading Hallucination Attacks high

Cascading Hallucination Attacks exploit the agent's inability to distinguish fact from fiction by getting a fabricated output embedded into memory, tool inputs, or downstream agents. Once embedded, the fabrication propagates, compounds, and is treated as evidence by later reasoning. The threat is the *propagation*, not the original <abbr class="hw-term" data-tip="A confident but fabricated model output that is not grounded in fact or source data." aria-label="A confident but fabricated model output that is not grounded in fact or source data." tabindex="0">hallucination</abbr>.

L3 cross-layer non-det AML.T0031AML.T0060AML.T0062

MAS Guide Multi-agent extensions of Step 2 6 entries

T28

Attacker gains unauthorised access to the vector database used by the RAG pipeline, exposing all indexed knowledge.

L2 AML.T0085AML.T0086AML.T0012 extends T1
T41

Ambiguous or inconsistently implemented MCP schemas cause client and server to interpret data differently, producing silent data corruption.

L3 non-det AML.T0067AML.T0031 extends T5

Step 3 Tools, Execution & Supply Chain 21 entries · 6 base + 15 MAS

Does the AI agent execute actions using tools, system commands, or external integrations?

T2
Tool Misuse high

Tool Misuse is the manipulation of an agent into abusing the tools it has been authorised to use. The actions stay within the agent's granted permissions; what attackers exploit is the gap between the *permission* to call a tool and the *intent* the user actually authorised. The OWASP catalog classifies *Agent Hijacking* under this threat: adversarial data the agent ingests and then acts on by issuing tool calls.

L3 cross-layer autonomynon-det AML.T0053AML.T0086AML.T0110
T3
Privilege Compromise critical

Privilege Compromise is the exploitation of mismanaged roles, dynamic permission inheritance, or overly broad scopes to escalate what an agent can do. Unlike conventional privilege escalation, the attack often does not require breaking access control. It only requires the agent to *use* permissions it already has, in combinations the system never anticipated. *Implicit privilege escalation* and *<abbr class="hw-term" data-tip="When a privileged component is tricked into misusing its authority on behalf of a less-privileged attacker." aria-label="When a privileged component is tricked into misusing its authority on behalf of a less-privileged attacker." tabindex="0">Confused Deputy</abbr>* failures are the canonical patterns.

L4L6 cross-layer autonomyidentity AML.T0012AML.T0055AML.T0083AML.T0098
T4
Resource Overload high

Resource Overload is the deliberate exhaustion of an agent's compute, memory, external service quotas, or downstream API budget. It looks like classical denial-of-service in its outcome, but the attack surface is different: agents *autonomously schedule, queue, and execute tasks across sessions*, can *self-trigger work*, and can *coordinate with other agents*, so a single trigger can fan out into exponential resource consumption.

L4 cross-layer autonomy AML.T0029AML.T0034AML.T0034.002AML.T0046
T11
Unexpected RCE and Code Attacks critical

Unexpected <abbr class="hw-term" data-tip="Remote Code Execution: an attacker running arbitrary code on the target system." aria-label="Remote Code Execution: an attacker running arbitrary code on the target system." tabindex="0">RCE</abbr> and Code Attacks exploit the fact that agents with code-execution or function-calling capabilities can be steered into running attacker-influenced code. Unlike classical RCE, the attacker may not need a memory-corruption bug. Natural language is the injection vector, and the agent itself produces the code that runs.

L3L4 autonomy AML.T0049AML.T0050AML.T0072AML.T0102
T16
Insecure Inter-Agent Protocol Abuse critical

Insecure Inter-Agent Protocol Abuse is the attack surface that opens once agents talk to each other (Agent-to-Agent / <abbr class="hw-term" data-tip="Agent-to-agent communication: messages passed directly between autonomous agents." aria-label="Agent-to-agent communication: messages passed directly between autonomous agents." tabindex="0">A2A</abbr>) or to tools (Model Context Protocol / <abbr class="hw-term" data-tip="Model Context Protocol: an open standard for connecting agents to tools and data sources." aria-label="Model Context Protocol: an open standard for connecting agents to tools and data sources." tabindex="0">MCP</abbr>) using protocols designed for collaboration rather than for adversarial trust. The attacker targets the trust embedded in these protocols by manipulating server responses, injecting context into tool descriptions, or exploiting ambiguous consent flows to mislead agent reasoning. When protocol specifications are loosely enforced, or implementations lack input validation and strong identity binding, attackers can hijack agent behaviour, escalate privileges, or bypass guardrails entirely.

L3L7 cross-layer a2a comm AML.T0073AML.T0074AML.T0080
T17
Supply Chain Compromise critical

Supply Chain Compromise covers vulnerable, malicious, outdated, or otherwise harmful upstream components that end up inside the agent: models, libraries, plugins, prompt templates, build pipelines, or framework updates. The compromise can manipulate agent behaviour, exfiltrate data, or run arbitrary code, and is amplified in agentic systems because the agent will autonomously *use* the compromised component across many runs.

L1L2L3 AML.T0010AML.T0019AML.T0058AML.T0109

MAS Guide Multi-agent extensions of Step 3 15 entries

T19

A workflow definition bug causes the agent to execute steps out of order or skip critical validation gates entirely.

L3 autonomy AML.T0053AML.T0081AML.T0067 extends T2
T21

State synchronisation failures across agents produce conflicting actions or silent denial of service for legitimate tasks.

L3 autonomy AML.T0053AML.T0081 extends T2
T22

Service account credentials accidentally exposed (e.g. committed to a public repository) grant an attacker direct access to privileged backend systems.

L4 AML.T0055AML.T0083AML.T0012 extends T3
T24

A bug in the dynamic policy engine prevents correct policies from being applied to new contexts, granting users capabilities they should not have.

L6 autonomy AML.T0012AML.T0081AML.T0067 extends T3
T32

An agent enters a runaway loop and submits transactions at high frequency, incurring cost and disrupting the broader agent ecosystem.

L3 autonomy AML.T0034AML.T0034.002AML.T0029 extends T4
T47

Attacker publishes a malicious MCP server masquerading as a legitimate one; agents connecting to it receive manipulated data or have credentials stolen.

L7 identity AML.T0074AML.T0110AML.T0109AML.T0058 extends T17

Step 4 Authentication & Identity 4 entries · 1 base + 3 MAS

Does the AI system rely on authentication to verify users, tools, or services?

MAS Guide Multi-agent extensions of Step 4 3 entries

T34

Compromise of an agent's blockchain wallet private keys enables fund theft and agent impersonation on-chain.

L4 identity AML.T0055AML.T0083AML.T0073 extends T9
T40

Attacker impersonates a legitimate MCP client via stolen credentials or auth bypass, gaining unauthorised access to server resources.

L3 identity AML.T0073AML.T0012AML.T0055 extends T9

Step 5 Human Engagement 2 entries

Does AI require human engagement to achieve its goals or function effectively?

Step 6 Multi-Agent 6 entries · 3 base + 3 MAS

Does the AI system rely on multiple interacting agents?

T12
Agent Communication Poisoning critical

Agent Communication Poisoning is the manipulation of inter-agent communication channels to inject false information, misdirect decisions, or corrupt shared knowledge in multi-agent systems. The threat is distinct from classical message tampering because the recipient agents *reason* over the message. Small, plausible-looking distortions can drive substantial behavioural change.

L2 cross-layer a2a comm AML.T0080AML.T0080.000
T13
Rogue Agents in Multi-Agent Systems critical

Rogue Agents are malicious or compromised agents operating inside a multi-agent system, exploiting trust mechanisms or workflow dependencies to manipulate decisions, exfiltrate data, or execute denial-of-service. The OWASP catalog includes the *infectious backdoor* concept: a single compromised agent's reasoning chain spreads through outputs that other agents consume, propagating malicious logic across the network.

L4L7 cross-layer a2a commidentity AML.T0061AML.T0081AML.T0110
T14
Human Attacks on Multi-Agent Systems high

Human Attacks on Multi-Agent Systems occur when adversaries exploit inter-agent delegation, trust relationships, and task dependencies to bypass security controls, escalate privileges, or disrupt workflows. The attacker treats the agent topology as the attack surface: by injecting deceptive tasks, rerouting priorities, or overwhelming agents with excessive assignments, they manipulate AI-driven decision-making in ways that are difficult to trace and mitigate because no single agent holds the full picture.

L4L7 cross-layer a2a commautonomy AML.T0073AML.T0053AML.T0086

MAS Guide Multi-agent extensions of Step 6 3 entries

T38

Multiple agents executing similar strategies inadvertently produce emergent behaviour that disrupts blockchain operation or market price.

L7 a2a comm AML.T0061AML.T0081AML.T0031 extends T13