New cyberattack can steal your data from Microsoft Copilot
A new hack called "Reprompt" lets attackers swipe your personal info from Microsoft Copilot Personal with just one click on a bad link.
Discovered by Varonis Threat Labs, this attack tricks users into clicking a phishing link, then quietly grabs things like your files and chat history by hijacking your session—no extra steps needed.
How does the reprompt attack actually work?
Reprompt uses a sneaky method called Parameter-to-Prompt injection. Basically, it loads malicious prompts through the 'q' URL parameter as soon as you open the page.
The attack repeats instructions to get around Copilot's defenses and keeps sending out your data even after you close the tab, making it hard to spot.
Is this still a problem?
Microsoft patched the vulnerability after being alerted in August 2025, so if you're up to date, you should be safe.
The enterprise version (Microsoft 365 Copilot) wasn't affected at all.
Unlike some other attacks that don't need any clicks, Reprompt only works if you click a sketchy link—so staying alert really helps.
What can I do to stay safe?
Don't click on links from people or places you don't trust, and be careful with what info you share with Copilot.
Double-check URLs for weird 'q' parameters if something seems off.
These small steps go a long way in keeping your data secure against tricks like Reprompt.