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.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
The worm is wrapped in a polymorphic envelope, executables containing the worm will be different every time the worm spreads.
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.
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 for Mimail.Q is available in the following FSAV updates:
Detection Type: PC
Technical Details: Ero Carrera; January 26th, 2004