Analysis by: MarfelTi
ALIASES:

Symantec: Infostealer.Bancos; Kaspersky: Trojan-Downloader.Win32.Homa.fkj

 THREAT SUBTYPE:

Information Stealer

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data. It attempts to steal information, such as user names and passwords, used when logging into certain banking or finance-related websites.

  TECHNICAL DETAILS

File Size: 2,614,272 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 23 Jun 2011

Arrival Details

This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This spyware drops the following files:

  • %Windows%\Rede.ini
  • {malware path}\logwindp.txt
  • %System%\drivers\trs.sys - detected as TSPY_BANKER.EST

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It drops the following copies of itself into the affected system:

  • %Application Data%\ctfmonn.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

Autostart Technique

This spyware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{malware file name} = {malware path and file name}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
@ = %Application Data%\ctfmonn.exe

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\ctfmonn

HKEY_CURRENT_USER\EnableLUA

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\EnableLUA
SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = 0

Information Theft

This spyware monitors the Internet Explorer (IE) activities of the affected system, specifically the address bar or title bar. It recreates a legitimate website with a spoofed login page if a user visits banking sites with the following strings in the address bar or title bar:

  • http://santander.com.br/portal/wps/script/templates/GCMRequest.do?page=6140
  • https://bankline.itau.com.br/lgnet/InternetPJ/HeaderItauEmpresas.htm?vol
  • https://bankline.itau.com.br/lgnet/InternetPJ/HeaderItauPlus.htm?vol
  • https://bankline.itau.com.br/lgnet/banklineprivateNovo.htm
  • https://bankline.itau.com.br/lgnet/itauf/bankline.htm
  • https://bankline.itau.com.br/lgnet/uniclass/banklineuniclass.htm
  • https://itaubankline.itau.com.br/lgnet/pers/banklinenovo.htm
  • https://sitenet.serasa.com.br/elementos_estrutura/login.htm
  • Banco do Brasil
  • Banco Itau
  • Internet Banking Caixa
  • Banco Bradesco
  • HSBC Bank Brasil
  • Banco HSBC
  • Banco Santander

The spoofed login overlaps the legitimate login area of the website, thus tricking the user into thinking that it is part of the IE window. The spoofed login page is located in a fixed area of the legitimate website. The said routine tricks the user into giving out sensitive account-related information. It then logs keystrokes entered by the user in the user name and password fields of the spoofed login page.

It attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

It attempts to steal information from the following banks and/or other financial institutions:

  • Banco do Brasil
  • Banco Itau
  • Internet Banking Caixa
  • Banco Bradesco
  • HSBC Bank Brasil
  • Banco HSBC
  • Banco Santander
  • Santander
  • Itau Global Bank
  • Serasa

Stolen Information

The stolen information is saved in the following file:

  • %Windows%\Rede.ini

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It sends the gathered information via HTTP POST to the following URL:

  • http://www.{BLOCKED}x.com.br/fotos/galeria.php

  SOLUTION

Minimum Scan Engine: 8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by TSPY_BANKER.CPF

    TSPY_BANKER.EST

Step 3

Identify and terminate files detected as TSPY_BANKER.CPF

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {malware file name} = {malware path and file name}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • @ = %Application Data%\ctfmonn.exe
  • In HKEY_CURRENT_USER\EnableLUA
    • SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • EnableLUA = 0

Step 5

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER
    • ctfmonn
  • In HKEY_CURRENT_USER
    • EnableLUA

Step 6

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Windows%\Rede.ini
  • {malware path}\logwindp.txt

Step 7

Scan your computer with your Trend Micro product to delete files detected as TSPY_BANKER.CPF. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

NOTES:

GENERAL RECOMMENDATION

  1. This malware is detected and removed by the latest Trend Micro anti-malware engine and pattern. Always keep pattern files and engines up-to-date. To know more about updating your Trend Micro product’s pattern, please refer to the following Trend Micro support page:
    http://esupport.trendmicro.com/9/How-do-I-manually-update-the-virus-pattern-of-my-Trend-Micro-Internet.aspx
    Note: The steps apply for specific products indicated in the page.
  2. To actively detect and protect your machine, enable real-time scanning of your Trend Micro anti-malware product. Refer to the following Trend Micro support page to know more about enabling real-time scanning in your Trend Micro product:
    Home Users: http://esupport.trendmicro.com/solution/en-us/1054798.aspx
    Business Users: http://esupport.trendmicro.com/Pages/How-do-I-enable-or-disable-the-Real-time-Protection-of-Trend-M-EN-1038331.aspx
  3. This malware creates and executes services in the affected system to make the malware stay resident in memory. Disable services that are related to this malware.
  4. For shared computers that are connected to a network, ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task.
  5. Enable firewall to protect against threats.
    http://esupport.trendmicro.com/3/How-do-I-enable-or-disable-the-Personal-Firewall-of-Trend-Micr-EN-1038273.aspx
  6. Enforce a strong password policy. Typically, a strong password consists of a mix of numbers, letters, and characters.


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