BKDR_KIMSUK.A

October 08, 2013
 Analysis by: Adrian Cofreros
 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:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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 arrives as a component bundled with malware/grayware packages.

It modifies registry entries to disable the Windows Firewall settings. This action allows this malware to perform its routines without being deteted by the Windows Firewall. It creates certain registry entries to disable applications related to security.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

102,400 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

13 Sep 2013

Payload:

Compromises system security

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.

It arrives as a component bundled with malware/grayware packages.

Installation

This backdoor drops the following files:

  • %System%\kbdlv2.dll - detected as BKDR_KIMSUK.A
  • %User Temp%\~DFE8B437DD7C417A6D.TMP - detected as BKDR_KIMSUK.A
  • %Program Files%\Common Files\System\Ole DB\oledvbs.inc - Contains system information

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Autostart Technique

This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
Type = "110"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
ImagePath = "%SystemRoot%\System32\svchost.exe -k DriverManage" - {hex values}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
DisplayName = "DriverManage"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage
Description = "{incomprehensible characters}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage\Parameters
ServiceDll = "%SystemRoot%\System32\kbdlv2.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage\Security
Security = "{hex values}"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage\Parameters

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DriverManage\Security

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
DriverManage = "DriverManage" - {hex values}

It modifies the following registry entries to disable the Windows Firewall settings:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\PublicProfile
EnableFirewall = "0"

It creates the following registry entries to disable applications related to security:

HKEY_LOCAL_MACHINE\SOFTWARE\AhnLab\
V3IS2007\InternetSec
FWRunMode = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Ahnlab\
V3IS80\is
fwmode = "0"

Information Theft

This backdoor retrieves the following information from the affected system:

  • System Information

NOTES:
This backdoor saves encrypted information collected by the following file name:

  • {System time MMDDHHmm}_sportsman.txt
It sends the encrypted information as an attachment to the following email accounts:
  • {BLOCKED}man@mail.bg
It may also send the information to the following email address:
  • {BLOCKED}112@hotmail.com
It saves the downloaded file attachment. The following downloaded file is decrypted via email and is executed:
  • %Program Files%\Common Files\System\Ole DB\sqlsoldb.exe
After the downloaded file executes, it is moved to the following folder and saved as:
  • %Windows%\taskmgr.exe
It requires other components to achieve other routine including backdoor capability.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.276.02

FIRST VSAPI PATTERN DATE:

13 Sep 2013

VSAPI OPR PATTERN File:

10.277.00

VSAPI OPR PATTERN Date:

14 Sep 2013

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

Restart in Safe Mode

[ Learn More ]

Step 3

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • DriverManage

Step 4

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\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • From: EnableFirewall = "0"
      To: EnableFirewall = "{system default}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\PublicProfile
    • From: EnableFirewall = "0"
      To: EnableFirewall = "{system default}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\AhnLab\V3IS2007\InternetSec
    • From: FWRunMode = "0"
      To: FWRunMode = "{system default}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Ahnlab\V3IS80\is
    • From: fwmode = "0"
      To: fwmode = "{system default}"

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\Microsoft\Windows NT\CurrentVersion\SvcHost
    • DriverManage = "DriverManage" - {Hex Values}

Step 6

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.
  • %Windows%\taskmgr.exe
  • %Program Files%\Common Files\System\Ole DB\oledvbs.inc

Step 7

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


Did this description help? Tell us how we did.