A Facebook Marketplace buyer arrived at a seller’s apartment to collect a keyboard. The seller wasn’t home and didn’t know anyone was coming. Meta’s AI assistant Muse had handled the conversation, shared his address, and arranged the visit without telling him.

We often write about AI misalignment and how to use AI agents and browsers safely. That can sound theoretical, but this is an example of the real-world risk when an agent is allowed to act on someone’s behalf.

Muse is Meta’s semi-autonomous AI assistant, released in the US in September. Meta promotes it as a personal assistant that can help users automate tasks, including responding to Facebook Marketplace messages. Unlike a conventional chatbot, which waits for a prompt and produces an answer, an AI agent may be authorized to take actions within connected apps.

We’ve written about a separate weakness in Muse that researchers considered dangerous. Reportedly, Muse was downloaded 3 million times in its first week.

According to Business Insider, a Facebook Marketplace seller turned on Muse to help handle a keyboard listing. He entered his address as the pickup location and approved automatic replies. Muse then shared that address with a prospective buyer, negotiated over the item, and arranged a visit, the seller said. He says Muse did not ask permission to share his address or arrange the visit, and did not tell him it was happening. The buyer arrived at the seller’s apartment expecting to complete the purchase, but the seller wasn’t home. The sale didn’t happen.

The reported incident is more than a privacy failure. It illustrates a broader AI-agent risk: An agent may treat permission to reply automatically as permission to share sensitive information or commit you to an in-person meeting. Meta says it is looking into the report.

How to use AI agents safely

Before enabling an AI agent, treat its setup screen as a security review. Do not assume that an integration with a trusted platform means the agent will understand your intentions or apply sensible limits automatically.

Pay particular attention to:

• Connected accounts: Review every service the agent can access, such as email, messages, calendars, cloud storage, shopping accounts, or social media profiles.
• Data access: Consider whether it can read addresses, contacts, photos, private messages, payment details, documents, or location data.
• Action permissions: Check whether the agent can send messages, post content, negotiate, make bookings, place orders, alter listings, or share information externally.
• Automatic actions: Apply settings that require approval before the agent sends, publishes, buys, deletes, or shares anything sensitive. Check how it will notify you about the plans it makes on your behalf.
• Audience controls: Confirm exactly who can receive information generated by the agent. “Anyone who messages me” is very different from “people I approve.”

Give an AI agent the least access necessary for the task. If you only want help writing replies, do not enable automatic sending. If you want an AI agent to manage a listing, use a public meeting location or a separate pickup address rather than your home address.

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A Facebook Marketplace buyer arrived at a seller’s apartment to collect a keyboard. The seller wasn’t home and didn’t know anyone was coming. Meta’s AI assistant Muse had handled the conversation, shared his address, and arranged the visit without telling him.

We often write about AI misalignment and how to use AI agents and browsers safely. That can sound theoretical, but this is an example of the real-world risk when an agent is allowed to act on someone’s behalf.

Muse is Meta’s semi-autonomous AI assistant, released in the US in September. Meta promotes it as a personal assistant that can help users automate tasks, including responding to Facebook Marketplace messages. Unlike a conventional chatbot, which waits for a prompt and produces an answer, an AI agent may be authorized to take actions within connected apps.

We’ve written about a separate weakness in Muse that researchers considered dangerous. Reportedly, Muse was downloaded 3 million times in its first week.

According to Business Insider, a Facebook Marketplace seller turned on Muse to help handle a keyboard listing. He entered his address as the pickup location and approved automatic replies. Muse then shared that address with a prospective buyer, negotiated over the item, and arranged a visit, the seller said. He says Muse did not ask permission to share his address or arrange the visit, and did not tell him it was happening. The buyer arrived at the seller’s apartment expecting to complete the purchase, but the seller wasn’t home. The sale didn’t happen.

The reported incident is more than a privacy failure. It illustrates a broader AI-agent risk: An agent may treat permission to reply automatically as permission to share sensitive information or commit you to an in-person meeting. Meta says it is looking into the report.

How to use AI agents safely

Before enabling an AI agent, treat its setup screen as a security review. Do not assume that an integration with a trusted platform means the agent will understand your intentions or apply sensible limits automatically.

Pay particular attention to:

• Connected accounts: Review every service the agent can access, such as email, messages, calendars, cloud storage, shopping accounts, or social media profiles.
• Data access: Consider whether it can read addresses, contacts, photos, private messages, payment details, documents, or location data.
• Action permissions: Check whether the agent can send messages, post content, negotiate, make bookings, place orders, alter listings, or share information externally.
• Automatic actions: Apply settings that require approval before the agent sends, publishes, buys, deletes, or shares anything sensitive. Check how it will notify you about the plans it makes on your behalf.
• Audience controls: Confirm exactly who can receive information generated by the agent. “Anyone who messages me” is very different from “people I approve.”

Give an AI agent the least access necessary for the task. If you only want help writing replies, do not enable automatic sending. If you want an AI agent to manage a listing, use a public meeting location or a separate pickup address rather than your home address.

---

Browse like no one’s watching. 

Malwarebytes Privacy VPN encrypts your connection and never logs what you do, so the next story you read doesn’t have to feel personal. Try it free → 

Mac security researcher Patrick Wardle says it’s trivial to turn Muse into “the ultimate backdoor.”

Increasingly, AI assistants are changing from tools that simply answer questions into agents that can plan tasks, use connected services, and take actions for us. These actions might include booking appointments, filling out forms, creating documents, making purchases, or interacting with email and calendars.

To do that, they need more permissions, account connections, and sensitive data. So, when Meta promised that “Muse is built from the ground up for privacy and security,” we did not expect an AI agent that can easily be manipulated into handing all that access to an attacker.

Meta says Muse can handle appointments, forms, customer-service interactions, purchases, document creation, and connections to services such as WhatsApp, email, calendars, and social platforms. It may also receive macOS permissions to access protected resources, including files, the microphone, camera, location, and calendars.

According to Ars Technica, Wardle found that a locally running application or terminal command could alter an undocumented Muse configuration setting that controls the server used for dictation transcription. By redirecting dictation traffic to an attacker-controlled server, an attacker could capture voice prompts and obtain the authentication token for the victim’s Muse account.

This is not a remote-code-execution vulnerability that can compromise an otherwise clean Mac. The attacker first needs a way to run code locally, such as through malware, a malicious application, or social engineering.

But as we have seen with infostealer malware finding its way onto Macs, that initial access is far from impossible.

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Traditional infostealer malware must independently locate browser data, credentials, documents, chat histories, and other valuable material. A compromised AI agent could lower that barrier by bundling access to multiple services and operating-system permissions behind one already authenticated interface.

Ultimately, this is not just about one unsafe configuration setting. It shows why AI agents need a higher security standard than ordinary apps.

How to stay safe

Wardle’s advice about Muse is simple: “Please don’t install.”

The same caution should apply to other AI agents.

The Open Worldwide Application Security Project (OWASP), a nonprofit foundation that provides free application-security guidance, lists prompt injection, tool abuse, privilege escalation, data exfiltration, excessive autonomy, memory poisoning, and sensitive-data exposure among the major security risks posed by AI agents.

A useful rule is that an AI agent should not have more access than it needs, and it should not be able to turn untrusted instructions into sensitive actions without meaningful checks. In practice, this means:

• Avoid giving a new agent broad access to email, chat apps, calendars, cloud storage, payment methods, and device permissions all at once.
• Regularly review and remove connections the agent does not genuinely need.
• Be aware of prompt injection. Do not assume that an AI agent will recognize malicious instructions embedded in a webpage, document, email, or other external content.
• Watch for unusual agent behavior, such as unexpected requests for new permissions, account reauthentication, external file sharing, or actions you did not initiate.

You should also protect your device against malware:

• Keep your software updated so attackers can’t use known vulnerabilities against you.
• Use an up-to-date, real-time anti-malware solution on all your devices.
• To protect against ClickFix attacks, don’t follow instructions you find on websites and in unsolicited messages that tell you to run commands.

---

From reporting threats to removing them.

Cybersecurity risks should never spread beyond a headline. Keep threats off your devices by downloading Malwarebytes today.

Mac security researcher Patrick Wardle says it’s trivial to turn Muse into “the ultimate backdoor.”

Increasingly, AI assistants are changing from tools that simply answer questions into agents that can plan tasks, use connected services, and take actions for us. These actions might include booking appointments, filling out forms, creating documents, making purchases, or interacting with email and calendars.

To do that, they need more permissions, account connections, and sensitive data. So, when Meta promised that “Muse is built from the ground up for privacy and security,” we did not expect an AI agent that can easily be manipulated into handing all that access to an attacker.

Meta says Muse can handle appointments, forms, customer-service interactions, purchases, document creation, and connections to services such as WhatsApp, email, calendars, and social platforms. It may also receive macOS permissions to access protected resources, including files, the microphone, camera, location, and calendars.

According to Ars Technica, Wardle found that a locally running application or terminal command could alter an undocumented Muse configuration setting that controls the server used for dictation transcription. By redirecting dictation traffic to an attacker-controlled server, an attacker could capture voice prompts and obtain the authentication token for the victim’s Muse account.

This is not a remote-code-execution vulnerability that can compromise an otherwise clean Mac. The attacker first needs a way to run code locally, such as through malware, a malicious application, or social engineering.

But as we have seen with infostealer malware finding its way onto Macs, that initial access is far from impossible.

---

---

Traditional infostealer malware must independently locate browser data, credentials, documents, chat histories, and other valuable material. A compromised AI agent could lower that barrier by bundling access to multiple services and operating-system permissions behind one already authenticated interface.

Ultimately, this is not just about one unsafe configuration setting. It shows why AI agents need a higher security standard than ordinary apps.

How to stay safe

Wardle’s advice about Muse is simple: “Please don’t install.”

The same caution should apply to other AI agents.

The Open Worldwide Application Security Project (OWASP), a nonprofit foundation that provides free application-security guidance, lists prompt injection, tool abuse, privilege escalation, data exfiltration, excessive autonomy, memory poisoning, and sensitive-data exposure among the major security risks posed by AI agents.

A useful rule is that an AI agent should not have more access than it needs, and it should not be able to turn untrusted instructions into sensitive actions without meaningful checks. In practice, this means:

• Avoid giving a new agent broad access to email, chat apps, calendars, cloud storage, payment methods, and device permissions all at once.
• Regularly review and remove connections the agent does not genuinely need.
• Be aware of prompt injection. Do not assume that an AI agent will recognize malicious instructions embedded in a webpage, document, email, or other external content.
• Watch for unusual agent behavior, such as unexpected requests for new permissions, account reauthentication, external file sharing, or actions you did not initiate.

You should also protect your device against malware:

• Keep your software updated so attackers can’t use known vulnerabilities against you.
• Use an up-to-date, real-time anti-malware solution on all your devices.
• To protect against ClickFix attacks, don’t follow instructions you find on websites and in unsolicited messages that tell you to run commands.

---

From reporting threats to removing them.

Cybersecurity risks should never spread beyond a headline. Keep threats off your devices by downloading Malwarebytes today.