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F-Secure Malware Information Pages: BZub.DO
[Summary] | [Disinfection] | [Detailed Description] | [Detection]

Name : BZub.DO
Alias:W32/BZub.DN, Trojan-Spy:Win32/BZub.do, Trojan-Spy.Win32.BZub.do
Size:100056
Type:Trojan-Spy
Category:Malware
Platform:W32
Date of Discovery:September 12, 2006
Radar

Summary
BZub.DO, a variant of BZub, is a Trojan. BZub.DO creates files in the Windows directory and steals logins, passwords, PINs, check words and other info related to logging to bank websites.
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Disinfection

Automatic Disinfection

Usually standalone malware (backdoors, worms, trojans, etc.) is automatically removed by F-Secure Anti-Virus (FSAV) starting from version 5.40. Malware files get automatically renamed by FSAV, so they can not be started any more. In some rare cases, when automatic disinfection is not possible, a user can select disinfection action by him/herself to make FSAV rename or delete an infected file. In some special cases it is recommended to use specific disinfection tools provided by F-Secure. They can be downloaded from our ftp site:

ftp://ftp.f-secure.com/anti-virus/tools/

F-Secure Anti-Virus can be purchased from our webshop or from our authorised distributors. A trial version F-Secure Anti-Virus, limited to 30 days, can be downloaded from our website:

http://www.f-secure.com/download-purchase/

All the latest versions of FSAV can download anti-virus database updates automatically. However, these updates can be also downloaded and installed manually from our web or ftp sites:

http://www.f-secure.com/download-purchase/updates.shtml


Manual Disinfection

To manually disinfect standalone malware (backdoors, worms, trojans, etc.) it's usually enough to delete all infected files from a computer and to restart it. Active malware files are usually locked by operating system so different disinfection approaches are required for different operating systems.
Please note that manual disinfection is a risky process, so it is recommended only for advanced users.

If Windows 95, 98 and ME operating system is used, it is recommended to restart a computer from a bootable system diskette and to delete an infected file from command prompt. For example if a malicious file named ABC.EXE is located in Windows folder, it is usually enough to type the following command at command prompt:

DEL C:\WINDOWS\ABC.EXE

and to press Enter. After that an infected file will be gone. If Windows NT, 2000 or XP is used, a malicious file has to be renamed with a different extension (for example .VIR) and then a system has to be restarted. After restart a renamed malicious file will no longer be active and it can be easily deleted manually.


Malware Disinfection Tools

F-Secure provides disinfection tools for certain malware. These tools can be downloaded from this webpage:

http://www.f-secure.com/download-purchase/tools.shtml

ftp://ftp.f-secure.com/anti-virus/tools/


Windows System Restore Issues

If Windows ME or XP is used, it is recommended to disable System Restore feature of these operating systems to prevent a computer from re-infection by an already removed malware. The fact is that System Restore feature of these operating systems might save an infected file into the special folder and copy it back to a hard drive it every time it's been renamed or deleted by F-Secure Anti-Virus or by a user. Instructions on how to disable System Restore feature are here:

Windows ME:
http://www.f-secure.com/v-descs/sfc_dis.shtml

Windows XP:
http://www.f-secure.com/v-descs/sfc_dis1.shtml

It is recommended to re-enable System Restore after disinfection in order to restore stable system configuration in the future, if any crash or incompatibility issue occurs.


Failed Disinfection

In some cases F-Secure Anti-Virus might not disinfect a system automatically. In this case please visit our Support pages:

http://support.f-secure.com/enu/home/virusproblem/howtoclean/
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Detailed Description
The BZub.DO trojan was spammed to a large number of people as an attachment to an e-mail message. The attachment name was rakningen.exe, the same file name that was recently used for a spammed variant of Haxdoor backdoor. The trojan drops a keylogger and spies against users of several banks.

After being run by the user, the trojan drops three files to the Window System folder. The dropped files represent the main spying component (ipv6monl.dll) and a keylogger (msn.exe and hook.dll). Both spying components are registered to start with every Windows session and remain active in memory at all times.

The main spying component steals information related to various on-line banking accounts. Customers of the following banks and on-line payment systems may be affected:

  • Barklays
  • E-Gold
  • Intelligent Finance
  • Nationwide's Internet Bank
  • Postbank


The trojan also steals the following info and sends it to a hacker:

  • HTTP mail password
  • HTTP mail user name
  • IE autocomplete fields data
  • IE protected storage data
  • MSN Explorer signup data
  • Outlook account passwords
  • POP server name
  • POP server password
  • POP server user name
  • SMTP e-mail address


The keylogger records all keystrokes on an infected computer and sends the stolen info to the hacker.
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Detection

F-Secure Anti-Virus detects this malware with the following updates:

[FSAV_Database_Version]

Version = 2006-09-12_09.
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F-Secure Corporation

Last Modified: September 18, 2006