W32.Magistr.39921 @mm

Due to an increased number of submissions, Symantec has upgraded this virus to a Category 3 rating on 9/6/2001.

W32.Magistr.39921@mm is a new variant of W32.Magistr.24876@mm.

Also Known As: I-Worm.Magistr.b, W32.Magistr.B@mm, W32/Magistr.b@MM

Type: Virus, Worm

Infection Length: 39,921 bytes

Virus Definitions: September 4, 2001

Threat Assessment:

 

Wild: Medium

Damage: High

Distribution: High

Wild:

• Number of infections: 50 - 999
• Number of sites: 3 - 9
• Geographical distribution: Medium
• Threat containment: Moderate
• Removal: Moderate

Damage:

• Payload:
  • Large scale e-mailing: Uses email addresses from the Windows and Eudora Address Book files, Outlook Express Sent Items folder, and Netscape Sent Items files.
  • Causes system instability: Overwrites hard drives, erases CMOS, flashes the BIOS.
  • Releases confidential info: It could send confidential Microsoft Word documents to others.

Distribution:

• Subject of email: Randomly generated text that can be up to 60 characters long.
• Name of attachment: One randomly named infected executable and several randomly selected text or document files
• Target of infection: All Windows PE files that are not .dll files.

Technical description:

Here is a list of the additional features and behavioral differences between W32.Magistr.39921@mm and W32.Magistr.24876@mm:

• Aware of Eudora address books (listed in Eudora.ini.)
• Deletes *.ntz while searching for files.
• Attempts to disable ZoneAlarm's user interface (this does not disable the ZoneAlarm firewall functionality).
• Adds an enty to the Shell=explore.exe line in the Boot section of System.ini, calling the W32.Magistr.Trojan.
• Searches for more Windows folders (Winnt, Windows, Win95, Win98, Winme, Win2000, Win2k, Winxp.)
• Emails an attachment that has a random extension (.exe, .bat, .pif, or .com.)
• Occasionally attaches .gifs to emails.
• The payload overwrites Ntldr.exe and Win.com on all drives with code that causes it to store garbage data in the first sector of the first IDE hard drive.



 

Removal instructions:

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and run a full system scan. Be sure that NAV is configured to scan all files.
3. Delete all files that are detected as W32.Magistr.39921@mm. If necessary, restore any W32.Magistr.39921@mm infected files from a clean backup.

NOTE: Files detected as W32.Magistr.Trojan must be restored from backup copies or extracted from the original installation CD. (These are the system files Ntldr.exe and Win.com.) Your system will not function properly without them. For information on how to do this, refer to your Windows documentation, or to one of the following documents:
• How to extract files in Windows 98 and Windows Me.
• How to extract files using Windows 2000 or Windows NT 4.0.

1. During the scan with NAV, note the name of any files infected by W32.Magistr.Trojan.
2. Click Start, and click Run.
3. Type the following, and then click OK.

edit c:\windows\system.ini

The MS-DOS Editor opens.

NOTE: If Windows is installed in a different location, make the appropriate path substitution.

4. In the [boot] section of the file, look for the following entry

shell=Explorer.exe

5. Position the cursor immediately to the right of Explorer.exe.
6. Press Shift+End to select all of the text to the right of Explorer.exe and then press Delete.
7. Click File, and Exit.
8. Click Yes when you are prompted whether to save the changes.

Write-up by: Peter Ferrie