Firefox has been continually gaining market share against main competitor Internet Explorer since its debut four years ago, which may be one reason why malware authors are looking for new avenues to infect computers, Canja said.
Users could be infected with the Trojan either from a drive-by download, which can infect a PC by exploiting a vulnerability in a browser, or by being duped into downloading it, Canja said.
When it runs on a PC, it registers itself in Firefox's system files as "Greasemonkey," a well-known collection of scripts that add extra functionality to Web pages rendered by Firefox.
BitDefender has updated its products to detect it, and other vendors will likely follow suit quickly, Canja said. Users could avoid it by only downloading signed, verified software, but that's a measure that restricts the usability of a PC, he said.
The malware is not present in Mozilla's repository of add-ons, Canja said. Mozilla had taken steps to ensure that its official site hosting add-ons -- also called extensions -- are free from malware.
In May, Mozilla acknowledged that the Vietnamese language pack for Firefox contained a bit of unwanted code. Although widely reported as a virus, the language actually contained a line of HTML code that would cause users to view unwanted advertisements.
Mozilla now scans new add-ons for malware. However, those scans will only detect known threats, and there was no signature in the security software Mozilla was using at the time that could detect the code.
Mozilla said the code probably ended up in the language pack after the PC of its developer became infected. More than 16,000 people downloaded the language pack, but only about 1,000 people regularly use it.
After the incident, Mozilla said it would scan add-ons in its repository when antivirus signatures were updated.
- 15 Non-Certified IT Skills Growing in Demand
- How 19 Tech Titans Target Healthcare
- Twitter Suffering From Growing Pains (and Facebook Comparisons)
- Agile Comes to Data Integration
- Slideshow: 7 security mistakes people make with their mobile device
- iOS vs. Android: Which is more secure?
- 11 sure signs you've been hacked
- What Datapipe customers need to know about the new PCI DSS 3.0 compliance standard This handy quick reference outlines what PCI DSS 3.0 is, who needs to be compliant and how Alert Logic solutions address the new...
- Defense Throughout the Vulnerability Life Cycle This whitepaper provides insight into how to leverage threat and log management technologies to protect your IT assets throughout their vulnerability life cycle.
- The Critical Role of Support in Your Enterprise Mobility Management Strategy Most business leaders underestimate the importance of tech support when they choose an EMM solution. Here's what to put on your checklist.
- Separating Work and Personal at the Platform Level: How BlackBerry Balance Works BlackBerry® Balance™ separates work from personal on the same mobile device, right at a platform level. Find out how it can work for...
- Live Webcast Best Practices for the Hyperconverged Enterprise Network To the Age of Constant Connectivity and Information overload
- Getting Ready for BlackBerry Enterprise Service 10.2 Find out how BlackBerry® Enterprise Service 10 helps organizations address the full spectrum of EMM challenges, while balancing the needs of both the...
- Containerization Options: How to Choose the Best DLP Solution for Your Organization This webcast outlines a framework for making the right choice when it comes to containerization approaches, along with the pros and cons of... All Networking White Papers | Webcasts