Technology

Watch Out! Google Gemini Flaw Could Turn Your Inbox Into a Phishing Hotspot

2025-07-13

Author: Nur

A Hidden Danger in Your Inbox

Google's Gemini for Workspace has a newfound vulnerability that lets cybercriminals create deceptive email summaries, making malicious messages look harmless. These generated summaries might not contain direct links or attachments, but they can still lead users to phishing websites!

This exploit cleverly uses hidden prompt injections embedded within emails, taking advantage of Gemini’s AI capabilities when crafting summaries.

How the Attack Works

Most recently revealed by Marco Figueroa, Mozilla's GenAI Bug Bounty Programs Manager, this technique comprises creating an email with illicit instructions artfully camouflaged in the text. By applying CSS to shrink the font size to zero and changing its color to white, attackers can lay a trap that goes unnoticed.

Since no attachments or visible links are included, the chances of the email reaching its intended target significantly increase.

Once the recipient opens the email and requests a summary from Gemini, the AI tool unwittingly complies with the hidden commands. For instance, Figueroa illustrated a scenario where Gemini generates a warning that claims the user’s Gmail password is compromised, paired with a fictional support number—enough to send numerous users into a panic.

Why This is a Big Deal

Many users might trust these summaries as part of Google's Workspace tools, making the deception incredibly effective. This vulnerability poses a serious risk in an age where phishing attempts are becoming increasingly sophisticated.

Steps to Stay Safe

Figueroa suggested several ways for security teams to combat such attacks. One strategy is to neutralize any content that’s styled to be hidden in emails. Additionally, implementing post-processing filters that flag messages containing urgent language, URLs, or phone numbers could provide another layer of protection.

Users should remain vigilant, recognizing that summaries from Gemini don’t always provide trustworthy security alerts.

What is Google Doing?

BleepingComputer reached out to Google for their take on these emerging threats. A spokesperson reaffirmed their commitment to strengthening defenses against such challenges, noting ongoing efforts to bolster their current security measures through rigorous testing.

While no evidence currently shows that Gemini has been manipulated as described by Figueroa, the potential for abuse highlights the need for constant vigilance in cybersecurity.

Final Thoughts

With cyber threats evolving rapidly, it’s crucial for users and organizations to stay informed about potential vulnerabilities and adopt defensive strategies. As the digital landscape continues to change, awareness and adaptation will be key in staying one step ahead of cybercriminals.