Threat Description

Mimail.Q

Details

Aliases: Mimail.Q, I-Worm.Mimail.q
Category: Malware
Type: Email-Worm
Platform: W32

Summary



Mimail.Q worm was first found on 26th of January, 2004. As with previous versions, the worm steals personal, and credit card information from users by asking them to fill a fake Microsoft form.



Removal



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Technical Details



The worm is wrapped in a polymorphic envelope, executables containing the worm will be different every time the worm spreads.

System Infection

When the worm's file is run, it registers itself as a service process and becomes invisible in Task List on Windows 9x systems. The the worm copies itself as "Sys32.exe" and "outlook.exe" file to Windows directory and creates a startup key for this file in System Registry:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "System" = "%windir%\sys32.exe"
 

where %windir% is Windows directory name.

After installation the worm looks for cookie files in shell folders and if it finds 'e-gold.com' string in any of them, it creates a special key in the Registry.

After initial startup the worm asks a user to fill a fake Microsoft form. Information from that form is saved to a file and is sent to the worm's author. The form pages look like that:

The collected data is saved to a file named "mminfo.txt" that is located in the root of C: drive.

The worm drops the following files onto a hard disk:

  • c:\mshome.hta - fake Microsoft form page
  • c:\logobig.gif - picture shown in the form page
  • c:\wind.gif - picture shown in the form page

The worm starts its main 3 threads only if it can resolve 'www.google.com' address i.e. when connection to Internet is available.

The worm listens to port 3000 for incoming traffic. When there's an incoming traffic, the worm creates a pipe and runs 'cmd.exe', giving the attacker a command line into the infected computer.

E-Mail propagation spreading

The worm was seeded in messages with the following format:

Subject: Hi my sweet Nancy!
Body:
Hi my sweet Nancy,
			
I have been thinking about you all night...
 I would like to apologize for the other night when we made beautiful love and
 did not use condoms.
 I know.. this was a mistake and I beg you to forgive me..
 Nancy, I miss you more than anything, please call me, I need you...
 Do you remember when we were having wild sex in my house? I remember it all
 like it was only yesterday.
 You said that the photos would not come out good, but you were wrong, they are
 great.
 I didn't want to show you the pictures at first, but.. now I think it's time
 for you to see them.
 Please look in the attachment and you will see what I mean.
 
 I love you with all my heart,
 Frank
 
 Attachment: photos.scr
			

When spreading by itself, this variant of the worm composes e-mail form a selection of text strings within its body.

The name of the attachment is composed as follows, the first part of the filename is chosen from:

my
 priv
 private
 prv
 the
 best
 super
 great
 cool
 wild
 sex
 fuck
 

With a separator selected from:

_ (underscore)
 - (dash)
 __ (double underscore)
 

Followed by a second word, form the list:

pic
 img
 phot
 photos
 pctrs
 images
 imgs
 scene
 plp
 act
 action
 

The extension of the attachment if chosen from the following list:

.pif
 .scr
 .exe
 .jpg.scr
 .jpg.pif
 .jpg.exe
 .gif.exe
 .gif.pif
 .gif.scr
 

To collect victim's e-mail addresses the worm scans all files on a hard drive except those with the following extensions:

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

The collected e-mail addresses are saved into "outlook.cfg" file located in Windows folder.

To send e-mails the worm tries to contact the recipient's SMTP server directly. For this purpose it tries to resolve the current user's DNS server and search for SMTP server info for recipient's domain.

Payload

Beside stealing user's data from a fake Microsoft webform, the worm also attempts to steal information from E-Gold online payment system users. It collects certain data to a file named TMPEG2.TXT that is located in the root of C: drive. The worm then encrypts this file and saves the contents to TMPGLD.TXT file. Then this file is sent by e-mail to an e-mail address that is hardcoded in the worm's body.

The worm contains the immature threat within its body:

*** GLOBAL WARNING: if any free email company or hosting company will
 close/filter my emai l/site accounts, it will be DDoS'ed in next version.
 WARNING: centrum.cz will be DDoS'ed in next versions, coz they have closed my
 mimail-email account. Who next? ***
 
 visit our friendly site www.blackgate.us
			

F-Secure is not aware of any possible relationship between "www.blackgate.us" and the creators of the worm.



Detection


Detection for Mimail.Q is available in the following FSAV updates:
Detection Type: PC
Database: 2004-01-26_02



Technical Details: Ero Carrera; January 26th, 2004


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