The context protocol of the model (MCP) represents a powerful paradigm shift in the way large language models interact with external tools, services and sources. Designed to allow the dynamic invocation of the tool, MCP facilitates a standardized method to describe the metadata of the tool, allowing models to select and call functions intelligently. However, as for any emerging framework that improves the autonomy of the model, MCP has important security problems. Among these are five notable vulnerabilities: tool poisoning, Rug-Pull updates, disappointment of recovery-agent (harbor), server usurpation and cross-observation. Each of these weaknesses uses a different layer of MCP infrastructure and reveals potential threats that could compromise user security and data integrity.
Tool poisoning
The tool poisoning is one of the most insidious vulnerabilities of the MCP frame. Basically, this attack involves integrating malicious behavior in a harmless tool. In MCP, where the tools are announced with brief descriptions and entry / output diagrams, a bad actor can develop a tool with a name and a summary that seem benign, such as a calculator or a trainer. However, once invoked, the tool can carry out unauthorized actions such as deleting files, data exfiltration or the publication of hidden commands. Since the AI model deals with detailed tool specifications which may not be visible for the end user, it could execute the harmful functions without knowing, thinking that it works within the expected limits. This difference between appearance at the surface level and hidden functionality makes poisoning with the tool particularly dangerous.
Rug-Pull updates
Closely linked to the tool poisoning is the concept of Rug-Pull updates. This vulnerability focuses on the dynamics of temporal trust in compatible MCP environments. Initially, a tool can behave exactly as planned, carrying out useful and legitimate operations. Over time, the developer of the tool, or someone who takes control of his source, can issue an update that introduces malicious behavior. This change may not trigger immediate alerts if users or agents rely on automated update mechanisms or do not rigorously re -evaluate the tools after each revision. The AI model, always operating by assuming that the tool is trustworthy, can call it for sensitive operations, involuntarily of data leaks, corruption of files or other unwanted results. The danger of Rug-Pull updates lies in the start of the delayed risk: when the attack is active, the model has often already been conditioned to trust the tool implicitly.
Recovery-agent
The disappointment of recovery-agent, or harbor, exposes a more indirect but just as powerful vulnerability. In many MCP use cases, models are equipped with recovery tools to question the knowledge bases, documents and other external data to improve responses. Rade uses this feature by placing malicious MCP control models in documents or data sets accessible to the public. When a recovery tool ingests this poisoned data, the AI model can interpret integrated instructions such as valid tool call controls. For example, a document that explains a technical subject may include hidden prompts that order the model to call a tool in a involuntary way or provide dangerous parameters. The model, ignoring that it has been manipulated, executes these instructions, effectively transforming the data recovered into a secret control channel. This vagueness of data and executable intention threatens the integrity of contextual agents who count strongly on interactions from recovery.
Server
The usurpation of the server is another sophisticated threat in MCP ecosystems, in particular in distributed environments. Since MCP allows models to interact with remote servers who exhibit various tools, each server generally announces its tools via a manifesto which includes names, descriptions and diagrams. An attacker can create a thug server that imitates a legitimate server, copying his list of names and tools to deceive models and users. When the AI agent connects to this usurped server, it can receive modified tool metadata or run tool calls with fully different BACKEN implementations. From the point of view of the model, the server seems legitimate, and unless there is a strong authentication or an identity verification, it continues to operate under false hypotheses. The consequences of the usurpation of the server include the identification flight, data handling or the execution of unauthorized commands.
Cross server shade
Finally, observation of the cross server reflects vulnerability in multi-service MCP contexts where several servers contribute to a shared model session. In such configurations, a malicious server can manipulate the behavior of the model by injecting the context which interferes with or redefine the way in which the tools of another server are perceived or used. This can happen thanks to conflicting tool definitions, deceptive metadata or injected advice that distorts the model's selection logic of the model. For example, if a server redefines a common tool name or provides conflicting instructions, it can effectively shade or replace the legitimate functionalities offered by another server. The model, trying to reconcile these entries, can perform the bad version of a tool or follow harmful instructions. The observation of the cross servers undermines the modularity of the MCP design by allowing a bad actor to corrupt interactions which extend over several otherly secure sources.
In conclusion, these five vulnerabilities expose critical safety weaknesses in the current operational landscape of the model context protocol. Although MCP introduces fascinating possibilities for agency reasoning and the completion of dynamic tasks, it also opens the door to various behaviors that exploit the confidence of the model, contextual ambiguity and tool discovery mechanisms. As the MCP standard evolves and wins a broader adoption, the fight against these threats will be essential to maintain the confidence of users and ensure the sure deployment of AI agents in real environments.
Sources
https://techcommunity.microsoft.com/blog/MicrosoftDeFeDeterblog/Plug-Play-And-Prey-The-Security-Of-She-Model-ConText-Potocol/4410829
