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BKDR_BOTIME.A

August 21, 2013
 Analysis by: Jaime Benigno Reyes
 PLATFORM:

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

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet


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

It executes then deletes itself afterward.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

31,232 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Jun 2013

Arrival Details

This backdoor 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 backdoor drops the following component file(s):

  • %system%\MSCTFIMEEXT.IME - detected as PTCH_REDUS.A

It executes then deletes itself afterward.

It injects codes into the following process(es):

  • svchost.exe

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\
Boot

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Keyboard Layouts\E6861806

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
ie = "{malware's location}\{malware name}"

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
id2 = "{16 alphanumeric characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
it2 = it2 = "{binary data}"

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\
Boot
Runner1 = "{encrypted chunk of codes}"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\Main
Start Page = "about:blank"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
PrivacyAdvanced = "0"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
EnableHttp1_1 = "1"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
CertificateRevocation = "1"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
DisableCachingOfSSLPages = "1"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Policies\Explorer
NoFavoritesMenu = "1"

It modifies the following registry entries:

HKEY_USERS\.DEFAULT\Keyboard Layout\
Preload
1 = "E6861806"

(Note: The default value data of the said registry entry is 00000409.)

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Zones\3
CurrentLevel = "0"

(Note: The default value data of the said registry entry is 69632.)

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Zones\3
1001 = "3"

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

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Zones\3
1201 = "0"

(Note: The default value data of the said registry entry is 3.)

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Zones\3
1601 = "0"

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

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Zones\3
1C00 = "0"

(Note: The default value data of the said registry entry is 65536.)

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download and execute arbitrary files.
  • Shut down the computer.
  • Steal system information.
  • List security-related processes.

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://ip.{BLOCKED}n.net
  • http://tp.{BLOCKED}n.net

NOTES:

This backdoor copies the file %system%\MSCTFIME.IME and save it as %system%\MSCTFIMEEXT.IME.

It modifies the copied file's export function "ImeInquire" and it will serve as it's autostart component.

It will then add the following registry entries to ensure its automatic execution whenever the keyboard is used:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layouts\E6861806
IME File = "MSCTFIMEEXT.IME"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layouts\E6861806
Layout File = "KBDUS.DLL"

It inject codes in svchost.exe's memory where it will decrypt and execute the chunk of codes in the following created registry entry:

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\Boot
Runner1 = "{encrypted chunk of codes}"

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  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

Remove malware/grayware files dropped/downloaded by BKDR_BOTIME.A

  • PTCH_REDUS.A

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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.

  • HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\Boot
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layouts\E6861806

Step 5

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\ODBC
    • ie = "{malware's location}\{malware name}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
    • id2 = "{16 alphanumeric characters}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
    • it2 = "{binary data}"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main
    • Start Page = "about:blank"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • PrivacyAdvanced = "0"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableHttp1_1 = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • CertificateRevocation = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • DisableCachingOfSSLPages = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoFavoritesMenu = "1"

Step 6

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_USERS\.DEFAULT\Keyboard Layout\Preload
    • From: 1 = "E6861806"
      To: 1 = "00000409"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: CurrentLevel = "0"
      To: CurrentLevel = "69632"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1001 = "3"
      To: 1001 = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1201 = "0"
      To: 1201 = "3"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1601 = "0"
      To: 1601 = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1C00 = "0"
      To: 1C00 = "65536"

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BOTIME.A. 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.


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