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Have you ever wondered how a simple click could compromise your personal data? Imagine receiving an apparently harmless email, but it contains a link capable of bypassing the most advanced protections. Discover how a team of researchers managed to outsmart Microsoft’s security systems with a method as simple as it is effective.
The 3 key points not to miss
Reprompt is a type of attack that exploited a vulnerability in Copilot, Microsoft’s artificial intelligence tool. This method allowed attackers to bypass existing security mechanisms by manipulating URLs. By using the “q” parameter, hackers could insert instructions to be executed directly by the chatbot.
The process often started with a phishing email containing a legitimate Copilot link. Once clicked, this link automatically injected a request, allowing attackers to access the victim’s personal data discreetly.
With this attack, hackers were able to extract various information, ranging from the victim’s name and location to their travel plans. By manipulating the URL parameters, attackers could ask the chatbot to disclose information such as “What files has the user accessed today?” or “Where does the user live?”
In the most severe scenarios, a continuous dialogue could be established between the hackers’ server and the victim’s Copilot account, thus allowing a significant volume of data to be siphoned in record time.
Upon the discovery of this flaw by researchers from the company Varonis, Microsoft was informed confidentially. The company quickly took measures to fix the vulnerability, updating Copilot Personal on January 13, 2026. It is important to note that Microsoft 365 Copilot was not affected by this flaw.
This rapid response underscores the importance for companies to remain vigilant and responsive to new cybersecurity threats.
Microsoft Copilot is a tool based on advanced language models, designed to assist users in various office and creative tasks. Launched in a context of rapid progress in artificial intelligence, Copilot aims to integrate conversational and suggestion capabilities into Microsoft products. Although designed to simplify and enhance the user experience, the development of Copilot is not without security challenges, as evidenced by the Reprompt incident.