Rootkit:W32/Mediyes, Rootkit.mediyes.a, Trojan.Mediyes, Rootkit.Win32.Mediyes


Rootkit:W32/Mediyes redirects web traffic to unsolicited sites; it also hides its components on the infected system.

Automatic action

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.

Manual removal

The user may elect to manually delete all components installed by the trojan.

Suspect a file is incorrectly detected (a False Positive)?

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 detection database 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.

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Submit a sample

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Technical Details

Rootkit:W32/Mediyes is installed onto a system as part of the payload of a trojan-dropper identified as Trojan:W32/Mediyes (alias Trojan-Dropper.Win32.Mediye, Trojan.Mediyes).

The trojan-dropper was originally digitally signed with a certificate stolen from Swiss company Conpavi AG; the certificates used have since been revoked by the relevant certification authority.


As the file appears to be signed with a legitimate certificate, the dropper may be unwittingly manually executed by the user.

On execution, the dropper will install a file to the following locations:

  • C:\WINDOWS\system32\d3dywd2ks.dll - 32-bit driver file detected as rootkit.mediyes.a
  • C:\WINDOWS\system32\xptgaldz.tsp

Note: Of two dropper samples analyzed, one variant will prompt the the user to reboot the machine, while the other is able to install the driver without requiring reboot.

The dropper makes a number of registry changes, and creates a mutex, then deletes itself from the system.


On reboot, the DLL file is injected in to a web browser process (Internet Explorer or Mozilla Firefox), where it will intercept requests sent to various search engines and redirect the requests to unsolicited sites.