If you translated this information into another language,
please check the Other Languages link for instructions how to upload it.
This virus is attached to newsgroup and e-mail messages as an attachment
called Happy99.exe. You cannot get infected with this virus just by reading
a newsgroup or e-mail message. You have to execute the attachment. Almost always,
the person who sent it does not know that they are sending it out. It does not
show up in their Outbox.
If you didn't execute the attachment, you can just delete it and move on.
You should never open an EXE, COM, SHS, BAT, VBS file or MS Office
document unless you know the source and its purpose and even then, check
it with an up-to-date antivirus program.
If you execute an infected attachment, it
will display a firework display which looks like this:
It will create two files in the Windows System folder, SKA.EXE and SKA.DLL.
SKA.EXE will be a copy of HAPPY99.EXE.
It will copy the original WSOCK32.DLL to WSOCK32.SKA.
Then it will modify WSOCK32.DLL without changing its size so it will try to
run SKA.DLL while posting to Usenet and sending E-Mail.
The SKA.DLL file will silently attach HAPPY99.EXE to a second copy of outgoing
newsgroup and e-mail messages with a barely noticable delay.
This second copy will have the same subject and recipient, but it will have an
The outgoing message will contain the header
but this is normally not visible.
It does not modify any other file besides WSOCK32.DLL.
WSOCK32.DLL is a regular part of Windows that provides a connnection to the
If it is unable to modify WSOCK32.DLL, then it will add SKA.EXE to the RunOnce
section of the registry and WSOCK32.DLL will be modified next time the
computer starts. It will still create WSOCK32.SKA even if it is unable to modify
This virus will keep a list of message recipients in the file LISTE.SKA in the
Windows System folder. It will try not to send the Happy99.exe file twice to the same
person. The size of SKA.EXE (and HAPPY99.EXE) is 10,000 bytes. The size
of SKA.DLL is 8,192 bytes.
This virus does not steal passwords, as some sources have reported.
It does not contain any payload other than the fireworks display. However, it
could overload an e-mail server if a lot of copies get passed around. Also, since
it gets passed along a lot, a
different virus could attach to HAPPY99.EXE somewhere along the way.
Without SKA.DLL and SKA.EXE, the modified WSOCK32.DLL cannot perform any viral
action. However using a modified WSOCK32.DLL could cause problems while
on the Internet. The most common problem that has been reported is invalid
page faults, but these can have other causes. Restoring the original WSOCK32.DLL will correct these
This virus does not affect Macs, DOS, Windows 3.x, OS/2,
Linux or WebTV. However, someone using one of those could pass it along
manually, for example by forwarding the message. Under Windows NT it will
create SKA.EXE, SKA.DLL, and WSOCK32.SKA but will fail to add itself to the registry or modify
WSOCK32.DLL. If you have NT, you don't have to follow the removal steps;
you can simply delete SKA.DLL, WSOCK32.SKA and SKA.EXE from inside Windows NT if you
would like. This virus is not able to infect WSOCK32.DLL if it has
the read-only attribute. Setting the read-only attribute after being infected
is useless. I caution you not to run HAPPY99.EXE even if WSOCK32.DLL is
read-only. Since it has passed through so many computers, a different virus
could attach to HAPPY99.EXE along the way.
Some people have asked whether it is always called HAPPY99.EXE. This virus
doesn't contain any code to change the name. However, it would be simple for a
person to change it to anything they like.
It contains the encrypted text:
"Is it a virus, a worm, a trojan? MOUT-MOUT Hybrid (c) Spanska 1999."
Spanska is the alias of a virus writer who has written several other viruses.
There are some automatic cleaners for this virus
or you could do it manually.
Steps marked optional are not absolutely necessary and are completely safe
to skip. If you're not comfortable with DOS, get someone knowledgable to help
you with this. These steps should be safe, even under unexpected circumstances,
but I can't make guarantees. Perform these at your own risk.
If you have Windows NT, you don't have to follow the removal steps.
If your not sure whether you are infected or not, then perform
step 10 to check if you're clean.
Click Start, then Shut Down, then "Restart Computer in MS-DOS mode", then click Yes.
It's important to exit Windows in order to be able to replace
the file WSOCK32.DLL which Windows normally has in use.
At the DOS prompt type these commands exactly and press enter at the end of each line:
If that doesn't work, try
Delete SKA.EXE and SKA.DLL by typing
If you get "File not found" you're either not infected or in the wrong
directory. Make sure you're in your Windows System directory; check to
see if you followed step 2 exactly. You can continue following the
instructions even if you get "File not found". It can't hurt to
keep on following the instructions.
The ATTRIB command is just in case WSOCK32.DLL has been made read-only
since the infection.
Answer "Yes" if it asks if you want to overwrite WSOCK32.DLL. Explanation:
WSOCK32.SKA is a backup of the original WSOCK32.DLL. You
are replacing the modified DLL with the original. If you get a "Sharing
violation" make sure you followed step 1.
Optional Delete WSOCK32.SKA by typing
You can leave WSOCK32.SKA on your system. It is a copy of your original WSOCK32.DLL
Do not delete WSOCK32.SKA if you are unable to replace WSOCK32.DLL with WSOCK32.SKA.
Return to Windows by typing
Optional Click Start, then Run, then type regedit in the text box, then click OK.
Click HKEY_LOCAL_MACHINE, then Software, then Microsoft, then Windows, then
CurrentVersion. Under RunOnce check for SKA.EXE and select it if it is there.
Press delete and then click Yes. Close Regedit. Don't change anything else
without making a backup of the registry first. If you don't find SKA.EXE in
the registry, it doesn't mean you're not infected. SKA.EXE is only added to
the registry if HAPPY99.EXE is unable to modify WSOCK32.DLL when you run
it. Also, you'll only find it in the registry if you haven't rebooted since
you ran HAPPY99.EXE.
Optional Choose Start, Programs, Accessories, Notepad, choose
File, then Open then type C:\WINDOWS\SYSTEM\LISTE.SKA in the File Name box.
Warn the people on the list, then delete LISTE.SKA.
Make it clear to the people you warn that they won't be infected
unless they ran happy99.exe, to avoid alarming them unnecessarily.
If you haven't sent out any infected e-mails, there won't be a LISTE.SKA.
Optional Delete the HAPPY99.EXE file. The location
of HAPPY99.EXE will vary depending on where you saved it. You
can delete it simply by dragging it to the Recycle Bin from within Windows or whatever method you prefer.
You may still have some messages with HAPPY99.EXE attached in your mailbox.
These cannot do anything unless you run them. You can delete them if you want to or just ignore them.
Optional If you aren't sure whether you are infected, choose
Start, then Find, then "Files or Folders". Then type WSOCK32.DLL in the "Named" box.
In the "Look in" box choose drive C: or whatever drive you have Windows on.
In the "Containing Text" box type "ska.dll" without the quotes.
Then click "Find Now". If you don't find any files, that means that WSOCK32.DLL
isn't the modified version.
If you don't have the modified WSOCK32.DLL,
the virus has no way to attach to e-mails, even if you have SKA.EXE, SKA.DLL,
or WSOCK32.SKA in the Windows System folder.
If you have SKA.EXE
in the RunOnce registry section, and you haven't deleted SKA.EXE, then the
virus will try to modify WSOCK32.DLL
the next time you restart the computer. If you would like to check if SKA.EXE
is in the registry, then do step 7.
If you don't have the modified WSOCK32.DLL, and SKA.EXE isn't in the registry,
the virus is completely inactive and is effectively removed.