[COMP] CIAC Bulletin-Explore Zip Worm

                             INFORMATION BULLETIN

                            ExploreZip (packed) Worm
                        Addition to CIAC Bulletin J-047

December 1, 1999 17:00 GMT                                        Number K-008
______________________________________________________________________________
PROBLEM:       A variant of the ExploreZip Worm (See CIAC Bulletin J-047) is 
               spreading rapidly. The new variant is a packed version of the 
               original worm and is not detected by existing antivirus 
               programs. The worm spreads by sending itself as an attachment 
               to e-mail. The worm is destructive, zeroing the contents of 
               files and making them unrecoverable. 
PLATFORM:      The worm runs on all Windows platforms but Outlook or Exchange 
               are needed to spread. 
DAMAGE:        The worm zeroes the contents of files making them 
unrecoverable 
               by any reasonable means. The worm specifically targets .h, .c, 
               .cpp, .asm, .doc, .xls, and .ppt files. 
SOLUTION:      Do not execute an e-mail attachment named zipped_files.exe as 
               this is the worm program. Update your antivirus software as 
               soon as updates are available. 
______________________________________________________________________________
VULNERABILITY  Risk is high: This worm spreads rapidly using your e-mail 
ASSESSMENT:    program to send itself to everyone in your e-mail inbox. 
______________________________________________________________________________

CIAC has information that the ExploreZip (packed) Worm is spreading rapidly.

The ExploreZip (packed) Worm is a variant of the ExploreZip worm described in 
CIAC bulletin J-047. This variant is only different from the original in that 
it is a packed executable. Packed executables are a form of file compression 
that is uncompressed on the fly when the program is executed. See the CIAC 
bulletin J-047 for the details of this worm.

The worm spreads as an attachment to an e-mail message that appears to be a 
reply to a message you have sent. The attachment is named zipped_files.exe 
and 
is supposed to be a self extracting archive of documents. When the attachment 
is run, it checks your e-mail inbox and sends a reply to every message it 
finds there. In the reply, it adds the text:

     Hi !
     I received your email and I shall send you a reply ASAP.
     Till then, take a look at the attached zipped docs.
     bye.

and attaches the worm program. After sending the e-mail messages with the 
attached worm to all your associates, the worm starts zeroing the contents of 
files with the following file extensions.

       .h .c. cpp .asm .doc .xls .ppt

Because this is a packed version of the original worm, current versions of 
most antivirus products do not detect it. Updates are already available or 
are 
expected momentarily.

If you have been infected and need to remove this worm by hand, perform these 
steps:

    1. For Windows 95, 98, open the WIN.INI file and remove the following 
line:

        run=C:\windows\system\Explore.exe

    or

        run=C:\windows\system\_setup.exe

    If  your windows\system directory is in a different location, then 
    the strings above will also be different.

    For Windows NT, run REGEDIT and remove the following entry:

        HKEY_CURRENT_USER\Software\Microsoft\Windows 
NT\CurrentVersion\Windows\Run 

    Value = Explore.exe or _setup.exe

    2. Delete the file C:\windows\system\Explore.exe or 
C:\windows\system\_setup.exe. Again, if your windows\system directory is in a 
different location, use that path instead of the two listed above.
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