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BAT_BANKER.ZIPA

May 28, 2013
 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware.

  TECHNICAL DETAILS

File Size:

9,287 bytes

File Type:

BAT

Memory Resident:

No

Initial Samples Received Date:

09 May 2013

Arrival Details

This Trojan may be dropped by other malware.

Installation

This Trojan drops the following non-malicious file:

  • %User Temp%\temp.temp - infection status indicator

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows NT\CurrentVersion\
Winlogon\SpecialAccounts\UserList
ADM123 = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Policies\Google\Chrome
AllowOutdatePlugins = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Internet Explorer\MAIN
Extensions Off Page = "http://br.msn.com"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Extensions Off Page = "http://br.msn.com"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
EnableConcurrentSessions = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
SpecialAccounts\UserList
ADM123 = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Policies\Google\Chrome
AlwaysAuthorizePlugins = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Google\Chrome
AllowOutdatePlugins = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Google\Chrome
AlwaysAuthorizePlugins = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\Terminal Services
MaxInstanceCount = "5"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server
AllowTSConnections = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server
fSingleSessionPerUser = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server\Licensing Core
EnableConcurrentSessions = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
AllowMultipleSessions = "1"

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\LSA
limitblankpassworduse = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server
fDenyTSConnections = "0"

(Note: The default value data of the said registry entry is 1.)

Other Details

This Trojan creates the following account(s), which it adds to the Administrators group:

  • ADM123

NOTES:

It also adds ADM123 to the following user groups:

  • Users
  • Remote Desktop Users

It may also add ADM123 to the following Portugese user groups:

  • administradores
  • Usurios da rea de trabalho remota

This may serve as an opening for attackers to remotely access the affected system.

It replace the legitimate termsrv.dll with its component, %User Temp\update.gif. Then it renames the legitimate termsrv.dll to termsrv.dll.bak.

Hence, malicious routines are exhibited in the system.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

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_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList
    • ADM123 = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Policies\Google\Chrome
    • AllowOutdatePlugins = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN
    • Extensions Off Page = "http://br.msn.com"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • Extensions Off Page = "http://br.msn.com"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • EnableConcurrentSessions = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList
    • ADM123 = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Policies\Google\Chrome
    • AlwaysAuthorizePlugins = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome
    • AllowOutdatePlugins = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome
    • AlwaysAuthorizePlugins = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services
    • MaxInstanceCount = "5"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
    • AllowTSConnections = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
    • fSingleSessionPerUser = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Licensing Core
    • EnableConcurrentSessions = "1"

Step 3

Restore this modified 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: AllowMultipleSessions = "1"
      To: AllowMultipleSessions = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\LSA
    • From: limitblankpassworduse = "0"
      To: limitblankpassworduse = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
    • From: fDenyTSConnections = "0"
      To: fDenyTSConnections = 1

Step 4

Search and delete these files

[ Learn More ]
There may be some 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.
  • %User Temp%\temp.temp
  • %User Temp%\update.gif

Step 5

Scan your computer with your Trend Micro product to delete files detected as BAT_BANKER.ZIPA. 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.

Step 6

Restore these deleted files from backup

*Note: Only Microsoft-related keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

 
  • termsrv.dll

NOTES:

To delete added user accounts:

1. Log-in as Administrator.

2. Open Computer Management. To do this, Click Start and right click My Computer/Computer Manage.

3. In the left panel of the Computer Management, double-click the following:

Local Users and Groups

4. In the right panel, locate and delete the account:

  • ADM123

5. Close Computer Management.


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