This is an Internet worm that spreads through IRC channels and also intends to spread via e-mail, but fails because of bugs in its code.
The worm has been placed by its author on a page on the www.geocities.com. The page has the title:
On 2 July 2000, the info about this page was announced to IRC channels and there were more than 1000 hits on that page for the first day. Fortunately, the worm had a bug in its e-mail infection routine, and it didn’t spread too far.
The “Jer” worm uses a primitive, but very effective way of penetrating computers. A Web site contains a script-program (the worm itself), which is automatically executed after a user opens an infected HTML page. Then a user receives a warning from the system whether to accept this unknown script or not. This method exploits so-called “mind breaches”: to avoid this annoying message, a user will answer “yes”. Right after this moment, the worm will be passed on to the computer.
The infected HTML page contains the VBS script in its body. Upon opening that page, the script automatically is executed and the worm gains control. It creates a copy of the infected HTML page in the Windows system directory with the JER.HTM name and registers it in the system registry in the autostart section:
As a result, the worm will be automatically executed on each Windows startup.
The worm then goes to the C:MIRC directory and (if such a directory exists) creates a “SCRIPT.INI” file that contains the commands for the mIRC client. The worm writes to this file a set of commands to send an infected JER.HTM file to every computer that connects to the same channel as the infected computer. Additionally, this script provides access to the local disk of the infected computer to the IRC user who has typed a specified script keyword.
The worm makes some more changes in the system registry:
The worm also changes the Windows registration information:
To restore system settings, the original registry values have to be restored.
NOTE: It is recommended that only experienced users fix the Registry keys by using the Registry Editor. Incorrect access can cause serious problems that may require you to reinstall Windows. For information about how to edit the registry, view the Changing Keys And Values online Help topic in the Registry Editor (REGEDIT.EXE).
The following keys have to be removed from the registry:
The following keys have to be changed to proper values: