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Aliases :

Glieder.I, Trojan.Win32.Glieder.i, W32/Glieder.I, TrojanDropper.Win32.Small.kv, TrojanDownloader.Win32.Agent.cj


Yet another Glieder variant has been spammed. The origin is an email message sent to many people. The message contains an attachment named FOTOS.ZIP. Inside the ZIP archive there is an HTML portion that uses a common exploit to launch an EXE file named CALC.EXE, which is also located inside the archive.


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.

Technical Details

Once the CALC.EXE file is launched it copies itself to the Windows System32 directory under the name DORIOT.EXE and adds Registry keys under:


to ensure the trojan is stared upon reboot. A file named GDQFW.EXE is then dropped onto the Windows System32 directory. This file is then injected into Explorer.exe process space through process memory manipulation. The dropper terminates at this stage.

The injected code from GDQFW.EXE is active while Explorer.exe is active. It performs various tasks which include monitoring various security related update programs and terminating them; checking predefined list of URLs for a particular file and if present - downloading and executing it. It also manipulates with cached URLs on the user's machine.