Category: Malware

Type: Trojan-Spy

Aliases: BZub.BS


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.


Automatic action

Based on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the detected program or file, or ask you for a desired action.

Knowledge Base

Find the latest advice in our Community Knowledge Base.

About the product

See the manual for your F-Secure product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

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