BZub.BL

Classification

Malware

Trojan-Spy

W32

BZub.BL

Summary

BZub.BL is a member of the BZub family of trojan spies.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.BZub.BL is downloaded and executed by Small.DOG.

Removal

Automatic action

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.

Suspect a file is incorrectly detected (a False Positive)?

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 detection database updates, then try scanning the file again.

  • Submit a sample

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    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.

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Submit a sample

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Technical Details

BZub.BL is downloaded and executed by Small.DOG from the following URL:

  • https://apte-hamburg.de/Deutsch/Aktuell/[REMOVED].exe

Once BZub.BL is executed, it drops a file named 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:

  • [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.BL also makes a copy of the existing file C:\lofg.xxx to C:\ewerufeassur8fr. It deletes the following files:

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

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

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

BZub.BL 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

It steals the logon details of bank account users that have the following strings:

  • app/ueberweisung.input.do
  • app/ueberweisung.prep.do
  • banking.postbank.de
  • banking.postbank.de/app/finanzstatus.reduziert.init.do
  • banking.postbank.de/app/kontoumsatz.umsatz.init.do
  • banking.postbank.de/app/legitimation.input.do
  • banking.postbank.de/app/ueberweisung.quittung.do
  • e-gold.com/acct/acct.asp
  • https://*.netbank.commbank.com.au/netbank/bankmain
  • https://banking.postbank.de/app/finanzstatus.init.do
  • https://banking.postbank.de/app/kontoumsatz.umsatz.init.do
  • https://banking.postbank.de/app/welcome.do
  • https://signin.ebay*/ws/eBayISAPI.dll
  • postbank.de

BZub.BL sends gathered information via FTP using any of the following files:

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