W32/Tracur.J, Trojan.Spy.Agent.OEV, Trojan-downloader.win32.agent.dter


Trojan-Downloader:W32/Tracur.J identifies a malicious DLL file that installs a malicious plug-in for the Internet Explorer and/or Mozilla Firefox web browsers in order to redirect searches to an unsolicited website.

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.

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

This file is probably dropped by a separate dropper program.


The DLL file is registered as a Browser Helper Object (BHO) with the Internet Explorer web browser. If the Mozilla Firefox web browser is installed, the file will also install a malicious extension (the browser's equivalent of a BHO) for Firefox.


Once installed, the BHO in either web browser will redirect searches made using various search engines to:

  • http://74.50.[...].107

The site may host more malicious content. The list of targeted search engines is hard-coded; targeted search engines are:

  • Ask
  • Snap
  • Hotbot
  • Gigablast
  • Alltheweb
  • Altavista
  • Lycos
  • AOL
  • Bing
  • Yahoo!
  • Google

Registry Changes

During installation, Tracur.J creates the following registry keys:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{989A5447-1A50-4D02-BA55-724A516C1370}
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{989A5447-1A50-4D02-BA55-724A516C1370}
  • HKEY_CLASSES_ROOT\CLSID\{989A5447-1A50-4D02-BA55-724A516C1370}
  • HKEY_CLASSES_ROOT\.fsharproj
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.fsharproj