Threat Description

Mimail.P

Details

Aliases: Mimail.P, I-Worm.Mimail.p, W32/Mimail.P@mm, Mimail.P
Category: Malware
Type: Email-Worm
Platform: W32

Summary


Mimail.P worm was first found on 7th of January, 2004. The worm spreads in e-mails as a ZIP archive named PP-APP.ZIP that contains the worm's executable with a random name. The worm steals personal, and credit card information from users by asking them to fill a fake PayPal form. Also the worm steals e-mail and news servers info, RAS info, passwords and e-mail lists.



Removal


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More

Detailed instructions for F-Secure security products are available in the documentation found in the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.



Technical Details


Installation to system

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 WINMGR32.EXE file to Windows directory and creates a startup key for this file in System Registry:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]  "WinMgr32" = "%windir%\winmgr32.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. This key is then checked when the worm activates its timer.

After initial startup the worm asks a userto fill a fake PayPal 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 TMPENC.TXT that is located in the root of C: drive.

The worm drops the following files onto a hard disk:

  • %windir%\zipzip.tmp - the worm's file inside a ZIP archive (store method)
  • %windir%\ee98af.tmp - the worm's executable file copy
  • c:\index.hta - fake Paypal form page 1
  • c:\index2.hta - fake Paypal form pages 2 and 3
  • c:\tmpny3.txt - information collected from the fake webform
  • c:\tmpcan3.txt - empty file

where %windir%\ is a Windows directory.

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

One of the worm's threads creates a file named TMPENC.TXT and saves the contents of TMPNY3.TXT file into it in encrypted form. Then the following files are deleted:

c:\index.hta  c:\index2.hta  c:\tmpny3.txt  c:\tmpcan3.txt   

Finally the encrypted contents of the webform (TMPENC.TXT file) are sent by e-mail to an e-mail address that is hardcoded in the worm's body. The same data is also uploaded to the www.aquarium-fish.ru website. After that the TMPENC.TXT file is deleted.

Being active, the worm listens to port 5555 for incoming traffic. When there's an incoming traffic, the worm creates a thread and communicates with the traffic source.

Spreading in e-mails

The worm spreads itself in e-mails inside a ZIP archive called PP-APP.ZIP. The worm's file inside that archive has a random name and EXE extension. The message sent by the worm looks like that:

From: donotreply@paypal.com    Subject:   GREAT NEW YEAR OFFER FROM PAYPAL.COM! [some random characters]    Body:   Dear PayPal.com Member,     We here at PayPal.com are pleased to announce that we have a  special New Year offer for you! If you currently have an account  with PayPal then you will be eligible to receive a terrific  prize from PayPal.com for the New Year. For a limited time only  PayPal is offering to add 10% of the total balance in your  PayPal account to your account and all you have to do is  register yourself within the next five business days with our  application (see attachment)!    If at this time you do not have a PayPal account of your own you  can also register yourself with our secure application and get  this great New Year bonus!  If you fill out the secure form we  have provided PayPal will create an account for you (it's free)  and you will receive a confirmation e-mail that your account has  been created.     That's not all!  If you resend this letter (with its attachment)  to all of your friends you may be eligible to receive another  New Year bonus because the 1000 PayPal members that send the  most of these to their friends will get the bonus.  If you are  one of these 1000 lucky members then PayPal will add 17% of your  total balance to your account!     Registration is simple.  Just unpack the attachment with WinZip,  run the application, and follow the instructions we have  provided.  If you have problems opening the application then you  may want to try downloading a free version of WinZip from  www.winzip.com    Do not miss your chance at this fantastic opportunity!  Thousands of our current customers have already received their  prizes and now it's your turn; so hurry up and take advantage of  this special offer!   Best of luck in the New Year,  PayPal.com Team  Attachment: pp-app.zip   

The worm does not use any exploits to make its file start automatically on a recipient's system. The worm will infect a recipient's computer only when he/she unpacks the executable file from the archive and runs it.

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

The worm changes the startup page of Internet Explorer to point to a JPG image related to George Bush.

Also the worm has the code similar to the one used in Sysbug spying trojan. The worm collects the following information from an infected computer:

Account Name  POP3 Password2  POP3 Server  POP3 User Name  NNTP Server  NNTP User Name  SMTP Server  SMTP Display Name  SMTP Email Address  SMTP Organization Name  RAS Information  INETCOMM Server Passwords   

This data is saved to a file called TMPPSW.TXT and this file sent by e-mail to an e-mail address that is hardcoded in the worm's body. The same data is also uploaded to the www.aquarium-fish.ru website.

Additionally the worm tries to upload the list of collected e-mails that it stores in the TMPEML.TXT file to the www.aquarium-fish.ru website. The e-mails stored in this file are specially selected by the worm. The selection criterion is the presence of one of the following substrings in e-mail address:

.ca  .au  .uk  .us  .edu  .gov  .mil  .de  .it  .ru  .fr  .info  .org  .net  .com  @email.msn.com  @prodigy.net  @safe-mail.net@excite.com  @zwallet.com  @erols.com  @bigpond.com  @usa.net  @bigfoot.com  @bellsouth.net  @attglobal.net  @att.net  @attbi.com  @email.it  @lycos.com  @sbcglobal.net  @shaw.ca  @themail.com  @verizon.net  @yahoo.com  @msn.com  @mail.com  @hotmail.com  @earthlink.net  @aol.com   

Beside stealing user's data from a fake PayPal 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.

It should be noted, that every time the worm sends out stolen data, it tries to connect to the www.aquarium-fish.ru website and access different PHP scripts there. In some cases the worm can download and run executable file from that website. The file is downloaded as C:\MM.EXE and activated.



Detection


Detection for Mimail.P is available in the following FSAV updates:

Detection Type: PC
Database: 2004-01-07_02



Technical Details:Alexey Podrezov; January 7th, 2004
Description Last Modified: Alexey Podrezov; January 8th, 2004


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