Security Researchers Found a Hidden Flaw in Microsoft Copilot That Let Hackers Steal Passwords
The short answer
A newly disclosed vulnerability in Microsoft Copilot allowed attackers to steal user passwords when a target clicked a malicious link — a direct risk for small businesses using Microsoft 365. If your team uses Microsoft 365 with Copilot enabled, check for and apply any pending Microsoft security updates — public disclosure of a flaw typically accelerates vendor patching.
- Microsoft Copilot
- cybersecurity
- Microsoft 365
- credential theft
- phishing
What happened
Security researchers disclosed a vulnerability in Microsoft Copilot involving a hidden input parameter that could be exploited to steal user passwords. According to Ars Technica, the attack required a target to click on a link, making it a credential-theft scenario rather than a self-propagating exploit — but still consequential for organizations where employees use Copilot as part of their daily work.
Microsoft Copilot is embedded across Microsoft 365 applications including Outlook, Teams, Word, and Excel — tools that form the core productivity stack for many small businesses. AI assistants integrated at this depth have access to emails, files, and internal communications, which raises the stakes compared with a standalone app vulnerability.
What it means for your business
If your team uses Microsoft 365 with Copilot enabled, check for and apply any pending Microsoft security updates — public disclosure of a flaw typically accelerates vendor patching. Remind employees not to click links in unsolicited messages, even those arriving through familiar channels like Teams or Outlook, where Copilot's presence can create a false sense of safety. Audit which employees hold Copilot licenses and what data those accounts can access; a credential stolen from an account with broad permissions causes significantly more damage than one from a limited account. This incident is a useful reminder that AI tools layered on top of existing software inherit — and can amplify — the security risks of both layers.
Source: Ars Technica