JS.Seeker

SUMMARY

JS.Seeker is a Trojan horse program that alters the default startup and search pages of your Web browser.

The Trojan horse sometimes arrives as a file named Runme.hta. This file runs only if the Windows Scripting Host is installed.

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (Intelligent Updater) December 19, 2000

Threat Assessment

Wild

• Wild Level: High
• Number of Infections: More than 1000
• Number of Sites: More than 10
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low
• Modifies Files: Registry

Distribution

• Distribution Level: Low
• Name of Attachment: Runme.hta
• Size of Attachment: 3 to 5 K

TECHNICAL DETAILS

When JS.Seeker is executed, it makes changes to the following registry keys:

HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMainStart Page
HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMainSearch Bar
HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMainDefault_Page_URL
HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMainDefault_Search_URL
HKEY_CURRENT_USERSoftwareNetscapeNetscape NavigatorMainHome Page

The original registry values are saved in the Windows folder as Backup1.reg and Backup2.reg .

The Trojan horse creates the file Homereg111.reg in the Windows folder and sets the previously mentioned registry keys to its own values. It then runs Removeit.hta, which deletes the file Runme.hta from the C:WindowsStart MenuProgramsStartup folder.

JS.Seeker also creates the Prefs.js file in the Windows folder. This is a JavaScript file that changes Netscape Preferences to its own.

Recommendations

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

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

To remove JS.Seeker you need to:

• Run a full system scan and delete any files that are detected as infected.
• Delete the Homereg111.reg and Prefs.js files.
• Restore original settings by merging Backup1.reg and Backup2.reg into the registry.
  

For instructions on how to do this, see the sections that follow.

To run a full system scan:

1. Make sure that Norton AntiVirus is set to scan all files.
2. Run a complete system scan.
3. Delete all files found to be infected with JS.Seeker.

To find and delete the Homereg111.reg and Prefs.js files:

1. Click Start, point to Find, and click Files or Folders.
2. Make sure that Look in is set to (C:) and that Include subfolders is checked.
3. In the Named box, type the following file names:
   
   homereg111.reg prefs.js
   
4. Click Find Now. Windows will find the files (if they exist) and display them in the lower pane of the Find dialog box.
   
   NOTE: You are about to delete files. One of them is Prefs.js. If you are using Netscape, there is a legitimate Netscape file that is named Prefs.js. If you delete the legitimate Prefs.js, it deletes your Netscape preferences. If you use Netscape, and do not want to do this, when the files are found, just delete copies of Prefs.js that are not in a Netscape subfolder. For example, if you find a copy of Prefs.js in the Windows folder, that does not belong to Netscape and should be deleted.
   
5. Select each displayed file, press Delete, and click Yes to confirm.
6. Leave the Find: All Files window open, and go on to the next section.

To find and merge Backup1.reg and Backup2.reg into the registry:

1. Click New Search, and click OK to confirm.
2. Make sure that Look in is set to (C:) and that Include subfolders is checked.
3. In the Named box, type the following file names:
   
   backup1.reg backup2.reg
   
4. When found, double-click each of these files to restore the registry settings.
5. Once the registry has been restored and the computer is working correctly, delete Backup1.reg and Backup2.reg.