This is a 32bit Worm that travels by sending email messages to users. It drops the file explore.exe and modifies either the WIN.INI (Win9x) or modifies the registry (WinNT).

This worm attempts to invoke the MAPI aware email applications as in MS Outlook, MS Outlook Express and MS Exchange. This worm replies to messages received by sending an an email message with the following body:

Hi <Name Of Recipient> I have received your email and I shall send you a reply ASAP. Till then take a look at the attached
zipped docs. bye

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

The subject line is not constant as the message is a reply to a message sent to the infected user. The worm (named "zipped_files.exe" as the attachment, with a file size of 120,495 bytes (with compression). The file has a Winzip icon which is designed to fool unsuspecting users to run it as a self-extracting file. User who run this attachment will be presented with a fake error message that says:

"Cannot open file: it does not appear to be a valid archive. If this file is part of a ZIP format backup set, insert the last disk of the backup set and try again. Please press F1 for help."

This worm has a payload. Immediately after execution it will search all local drives for the following files types .c, .cpp, .h, .asm, .doc, .xls, or .ppt. When found, they are opened for write and immediately closed leaving them with a zero byte count. Approximately 30 minutes after infection this process is repeated.

This worm will locate systems drives which are NOT mapped drives using functions from MPR.DLL and Network Neighborhood! On these systems, the WIN.INI is modified with a run statement to load a file called _SETUP.EXE from the Windows path, and the file _SETUP.EXE is copied to the Windows path.
These systems will become infected when restarted. This worm will only try to such systems once, whereas systems which are mapped drives are constantly attempted to re-infect. Secondly, a machine infected via another share will switch between _setup and explore per reboot.

These files with zero bytes are unrecoverable!
 

W32/ExploreZip worm removal under Windows 95/98

1. Remove the line "run = c:\windows\system\explore.exe" from
"\windows\win.ini"

2. Remove any instances of the worm as identified by Sweep.

3. Restart the machine, as the worm may still be an active task.
(You may need to close any such active tasks first).
 

W32/ExploreZip worm removal under Windows NT

1. Remove the registry entry:
HCU\Software\Microsoft\WindowsNT\
CurrentVersion\Windows\run

This will refer to "\WINNT\SYSTEM32\EXPLORE.EXE"

2. Delete the file EXPLORE.EXE from the "\WINNT\SYSTEM32" directory
You may need to enter Windows NT Task Manager, choose the
"Processes" tab, and select "End Process" for any instance of
EXPLORE.EXE.

W32/ExploreZip searches all accessible network drives for other installations of Windows 95/98. The worm will install a file called _SETUP.EXE and make a change to WIN.INI so that is run next time the remote copy of Windows 95/98 is started.

If installations of Windows NT are found during the search of network drives W32/ExploreZip will install the _SETUP.EXE file and make the change to WIN.INI, but the file will not be run when the Windows NT machine is restarted. _SETUP.EXE would need to be run manually on the remote machine to apply its registry changes and become active.

If remote Windows installations are affected in this way you should delete the _SETUP.EXE and adjust the WIN.INI and registry accordingly