Openstream.T is Java applet based trojan downloader, that will download and execute a trojan that will download spyware and adware into the system.
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.
Openstream.T comes in a signed Java JAR file, that will download and activate if user uses a web browser that supports Java. Before letting the trojan to execute the Java runtime, will ask user whether he wants the signed Java application to run.
If user answers no, the trojan will not execute.
If user answers yes, the trojan will download an Win32 EXE trojan that will download further trojans.
Openstream will run basically under any browser which supports Java, and probably also under other operating systems than Windows. However as the only payload the trojan has is downloading Win32 EXE, the trojan is harmless in other operating systems than windows.