Cidra.D was discovered on 10th of March 2004. It's a trojan proxy, allowing to use users' computers to relay information, i.e. unsolicited email.
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 trojan will add an entry to the Windows registry aiming at being run every time Windows starts. The key will be:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run\UsbD]
Which will point where the file is initially run from.
Cidra.D does not spread by itself. It was massively spammed.
It will relay connections though infected computers, giving its creator a massively distributed distribution channel for spam and other content.