Security researchers at LayerX uncovered a design-level weakness affecting Claude Desktop Extensions (DXT), the extension framework tied to Anthropic’s assistant.
The flaw enables a zero-click remote code execution (RCE) scenario, where an attacker can gain control of a victim’s machine without them knowingly running anything malicious.
Where the problem really lies
Unlike traditional browser extensions that operate inside strict sandboxes, DXT components act as bridges between the AI model and the local operating system. These connectors run with the same privileges as the logged-in user. That means if the AI is persuaded to run a system command, the action isn’t limited — it can access files, credentials, and system settings.
This creates a dangerous situation:
AI tools designed to chain tasks together for convenience may also chain untrusted data to high-privilege execution tools.
How the attack works
The proof-of-concept attack is surprisingly simple. It starts with something harmless-looking: a calendar entry.
An attacker places a specially crafted event in a shared or invited Google Calendar entry. Hidden inside the description are instructions to pull files from a remote repository and execute them.
Later, the victim asks the AI assistant something normal, like checking their calendar and handling pending items. The model interprets this broadly. Seeing “tasks” in the calendar entry, it autonomously:
- Reads the event details
- Pulls code from the attacker’s repository
- Runs the downloaded script
make.batthrough a local extension
No warning appears that system-level commands are being executed. From the user’s perspective, they only asked for help managing their schedule. Behind the scenes, their machine is now compromised.
What makes this vulnerability different is that nothing “crashes” or overflows. The AI is doing exactly what it was built to do: connect tools, interpret context, and complete tasks. The breakdown happens at the trust boundary.
Public or low-trust sources like calendars, email, or documents are treated as valid inputs. But the system does not enforce strict rules preventing those inputs from triggering high-privilege operations. The AI lacks the judgment humans use instinctively — understanding that calendar text should never lead to code execution.
This research is a warning for the entire AI ecosystem. As assistants evolve from chatbots into operating system helpers, they gain access to:
- Local files
- Developer tools
- Automation frameworks
- Credentials and tokens
That convenience also creates a new attack surface: manipulating the data the AI reads, rather than attacking software directly.
What users and teams should do
Until architectural safeguards are introduced, the safest move is reducing the blast radius:
- Avoid connecting AI assistants to both external data sources (email, calendars, shared docs) and high-privilege local execution tools at the same time.
- Disconnect or limit local extensions that can run system commands.
- Treat AI workflow automation like privileged code, not a harmless assistant feature.
This incident shows that AI security is no longer just about model misuse or prompt injection. The real risk lies in autonomous tool chaining — where helpful automation quietly crosses security boundaries humans would never cross.
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