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BZub.BS is a member of the BZub family of trojan spyware. These types of trojans compromise system security by providing authentication information (logon, passwords, credit card numbers, etc.) to malicious users. This trojan steals the logon information of some Online German Bank accounts. Aside from that, it also steals email accounts and passwords that are stored in the user's computer system.


Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

There are some reports from customers that BZub.BS arrives via spam mail. See the screenshot below:

This malware has two components:

  • Spammed file - Rakningen.exe (Installer)
  • Ipv6mons.dll (Contains malicious routines and is injected in Internet Explorer)

Upon the execution of Rakningen.exe, it will install its .dll component by dropping the file Ipv6mons.dll into the Windows Systems Directory. It adds several encrypted or random registry values under the following subkey as its auto start technique:

  • [SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\load]

The registry values are the following:

  • cmpid
  • forwas
  • h
  • net_insll
  • nw
  • worg
  • wspopp

Moreover, it registers itself as a Browser Helper Object (BHO) using the following registry entries:

  • [HKEY_CLASSES_ROOT\CLSID\\InprocServer32] @ = "{systemdir}\ipv6mons.dll"
  • [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\\InprocServer32] @ = "{systemdir}\ipv6mons.dll"

It also registers its Internet Explorer as an authorized application to prevent the Windows Firewall from blocking network transactions through the said program:

  • (systemdir)[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess \Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List] " {Program Files}\Internet Explorer\IEXPLORE.EXE" = " {Program Files} \Internet Explorer\IEXPLORE.EXE:*:Enabled:Internet Explorer"

BZub.BS also makes a copy of the existing file C:\ to C:\ewerufeassur8fr.It deletes the following files:

  • C:\clearsdingdrfive
  • C:\test.txt

BZub.BS connects to the following FTP site:


Creates a file named info.txt containing information about the infected system:

  • Computer ID
  • Computer name
  • Country/Region
  • IP Address
  • Windows version

Steals information about the following by monitoring websites/forms and querying some registries:

  • Bank logon details
  • Cache password
  • Hotmail smtp/pop3 server
  • IEAutoCompleteFields
  • MSN Explorer Signup
  • Outlook Express

The malware steals logon details to banks that have the following strings:

  • app/
  • app/
  • https://*
  • https://signin.ebay*/ws/eBayISAPI.dll

This malware sends gathered information via FTP using any of the following files:

  • form.txt
  • info.txt
  • shot.txt