Yamanner is a JavaScript worm that targets Yahoo! web-based email and groups.
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
The Yamanner worm activates by just opening an infected email message with Internet Explorer. To do this it uses a 0-day vulnerability in the Yahoo! Mail system.
Yamanner builds its email messages and sends them to the infected user's contacts. The sent emails look as follows:
The worm resides inside the email body. It also tries to open a web page in another browser window.