Threat description




Mimail.L worm was found on 1st of December, 2003. It is a variant of the Mimail worm family.

This worm sends messages which pretend to be very personal and contain pictures. The attached file is a ZIP that contains the worm.

The other type of message it sends will look like the recipients credit card would be billed for buying child porn, possibly scaring and confusing the recipients.


Manual disinfection of an Mimail.L infected computer consists of the following steps:

1, Remove the registry value


2, Restart the computer

3, Delete '%WinDir%\svchost.exe' (where %WinDir% is the Windows Directory, typically c:\windows\ or c:\winnt).

Technical Details

The worm spreads in UPX packed form. The unpacked worm body is 24608 bytes in size and was written in C language.

Email Spreading

The virus sends two types of messages. One of them is sent with an infected attachment with the following text:

Hi Greg its Wendy.   I was shocked, when I found out that it wasn't you but your  twin brother!!!  That's amazing, you're as like as two  peas. No one in bed is better than you Greg. I remember, I  remember everything very well, that promised you to tell  how it was, I'll give you a call today after 9.        I'm so thankful to you, for acquainted me to your brother.  I think we can do i t on the next Saturday all three  together? What do you think? O yes, as you wanted I've made  a few pictures check them out in archive, I hope they will  excite you, and you will dream of our new meeting...  Wendy.  Attachment: wendy.zip 			  

The other message when sent by the virus does not contain any attachment but the worm has reportedly been seeded with the following text and an attachment called 'test.exe':

Good afternoon,  We are going to bill your credit card for amount of $22.95  on a weekly basis.  Free pack of child porn CDs is already  on the way to your billing address.  If you want to cancel  membership and your CD pack please email order and credit  card details to security@europe.spamhaus.org     Are you ready for all types of underage porn?  We have the  best selection for every taste!  Just click the secret  links below and have fun:    www.authorizenet.com  disney.go.com  www.spamcop.net  www.carderplanet.net  www.cardcops.com  www.register.com  www.spews.org  www.spamhaus.org    Nude boys under 16!  Nude girls under 16!  Incest, a daddy & a daughter!  We have everything you have ever dreamed for!   

This message is meant to scare and confuse the recipient and probably to hurt the reputation of the organizations mentioned in the mail.

The worm collects email addresses from files on the infected computer. It recursively searches through the user's document folders and looks into all the files whose extension is not on the following list:

"bmp"  "jpg"  "gif"  "exe"  "dll"  "avi"  "mpg"  "mp3"  "vxd"  "ocx"  "psd"  "tif"  "zip"  "rar"  "pdf"  "cab"  "wav"  "com"   

Using its own SMTP engine it sends emails with the malicious attachment. To find the SMTP server of the target email address the worm does an MX lookup using a predefined public DNS server.

System Infection

When started, Mimail.L first copies itself to the Windows Directory as 'svchost.exe'. This copy is added to the registry as


to make sure the worm is started when Windows starts.

The worm creates several temporary files in the Windows directory:

%WinDir%\x8wui12s.tmp - worm packed into a ZIP file  %WinDir%\xu39reu.tmp  - copy of the worm  %WinDir%\xu298da.tmp  - list of collected email addresses   

Computers infected with Mimail.L perform Distributed Denial-of-Service attacks on the following sites:

www.authorizenet.com  disney.go.com  www.spamcop.net  www.carderplanet.net  www.cardcops.com  www.register.com  www.spews.org  www.spamhaus.org   

Mimail.L also contains this text which is never shown:

*** Made in France. ***  virmakers   

Detection in F-Secure Anti-Virus was published in update number:

Detection Type: PC

Database: 2003-12-01_03

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