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15 June 2004
13 February 2007
Systems Affected:
CVE References:

Downloader.Ject is a Trojan horse that attempts to download and install a file by exploiting the vulnerabilities in Internet Explorer (BID 10472, BID 10473). The Trojan is triggered by visiting a Web site that contains the exploit code.

For additional information, read the Microsoft Internet Knowledge Base article Information Services (IIS) 5.0 – Download.Ject Detection and Recovery Advisory (Article 871277) .

Microsoft has released a configuration change to protect against this threat. For more information, read the article What You Should Know About Download.Ject .

This vulnerability was originally reported on June 6, 2004. Refer to for additional information.

The Microsoft update that fixes this vulnerability is described in Microsoft Security Bulletin MS04-025. Cumulative Security Update for Internet Explorer (Article 867801) .

Note: Virus definitions dated prior to June 16, 2004, may detect this threat as Bloodhound.Exploit.10.

Note: Virus definitions dated June 7th, 2006 or earlier may detect this threat as Download.Ject.

Antivirus Protection Dates

  • Initial Rapid Release version 16 June 2004
  • Latest Rapid Release version 07 May 2019 revision 006
  • Initial Daily Certified version 16 June 2004 revision 036
  • Latest Daily Certified version 07 May 2019 revision 008
  • Initial Weekly Certified release date 16 June 2004
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Downloader.Ject attempts to download and execute a file using the cross-zone scripting exploit in Internet Explorer, with redirection and delayed script injection, through a modal dialog box.

As this notification was written, Downloader.Ject attempts to download and install an adware component. Symantec antivirus products, which support security risk detection, detect this adware as Adware.VirtuMonde . The file is downloaded to C:\, and then is installed.


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.

At this time, there is no removal required for the Trojan itself because it runs from a Web site. The detection indicates that it has been detected on the Web site and stopped. However, if the Trojan was successful in downloading Adware.VirtuMonde , it should be removed.

Writeup By: Neal Hindocha