GhostPoster: Extensions that seem useful but steal your banking data when you're not careful

We all use browser extensions. Whether it's an "AdBlock" to get rid of annoying ads on YouTube, or a free VPN to watch movies from other countries, these little programs make our lives easier. But what if I told you that the useful "button" you just installed is actually a digital spy?

Recently, security experts discovered a threat called GhostPoster. Over 50,000 users have already fallen into the trap. At Altanet Craiova we believe that prevention is better than cure, so we explain how to recognize these traps before you click "Install".

What is GhostPoster and how does it hide?

GhostPoster is not a regular virus that immediately locks up your computer. It is much more cunning. Hackers create extensions that seem legitimate (for example, a PDF file converter or a fast VPN) and upload them to official app stores.

Their trick is ingenious: the dangerous code is not visible at first glance. It is hidden even in the images or logo of the extension. When your browser loads that little icon, it unwittingly activates the virus. It is like receiving a Trojan horse, but in miniature.

Why is it difficult to detect?

Most viruses attack immediately. GhostPoster is patient. After you install it, it can lie "asleep" for a few days or even weeks. It behaves normally, does its promised job (for example, it even blocks ads), earning your trust.

Only after you get used to it does the attack begin. This delay often fools even Google or Mozilla's automatic security systems.

What are the risks for infected users?

Once activated, GhostPoster takes control of your browser. Here's what it can do without your knowledge:

• Redirect payments: When you want to pay a bill or buy something online, you can change the recipient of the money at the last second.
• Disable protection: It can turn off other security extensions or antivirus, leaving the door open for other viruses.
• Steals saved data: If you have the habit of clicking "Save Password" in your browser for Facebook or your bank account, that data goes directly to hackers.

How do you protect yourself before installing something?

You don't have to give up extensions, you just have to be selective. Follow these three golden rules:

• Check the number of users and reviews: If an extension only has 50 downloads and 3 5-star reviews that sound fake (or are in Chinese/Russian), avoid it. Look for extensions used by millions of people.
• Read permissions: When you install something, a window pops up asking for permissions. If a "Flashlight" or "Calculator" extension asks for permission to "read and modify all data from websites you visit," say NO. It doesn't need that data.
• Install only from official sources: Even though viruses sometimes escape there, Chrome Web Store or Firefox Add-ons are much safer than dubious sites on the internet.

Conclusion

GhostPoster teaches us an important lesson: in the digital world, if something is free and too good to be true, you are probably the product (or victim). Clean up your browser regularly and delete extensions you no longer use.

Is your computer running slow or do you suspect that you installed something wrong? Our team offers you IT services for virus removal and optimization. Visit our contact page and let us take care of the technical side.

This material is part of Altanet's educational series on digital security. Want to know what other risks you are exposed to this year? See Complete list of cyber threats in 2026.