Ouch.A is a Java applet based trojan that downloads and installs WinShow (winshow.dll) spyware on the system.
Ouch activates when user views a web page or HTML email that contains reference to the trojan file.
Ouch does not replicate and does not infect the host system, the only operations it does is to download and install WinShow spyware component.
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.
When a JAR file containing the trojan is executed it uses Microsoft Internet Explorer VerifierBug vulnerability to get full privileges by escaping the Java security, and execute its code. Then the trojan downloads the winshow.dll into windows directory (default C:\Windows) and registers it with regsvr32.
To remove Ouch.A from your system apply the fix to the Java VM vulnerability and clear temporary Internet files cache
Further information about the vulnerability in the Microsoft Java VM, including a fix, is available at:
https://www.microsoft.com/technet/security/bulletin/ms03-011.asp