BKDR_ZEGOST.HJH


 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

100,352 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

19 Dec 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.

Autostart Technique

This backdoor registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\M020utiWindows\Parameters

Other System Modifications

This backdoor deletes the following files:

  • G®‰

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\M020utiWindows
Load_Path = "{malware path and file name}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\M020utiWindows
ConnectGroup = "Default"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\M020utiWindows
Description = "Microsoft Device Manager,Stop service will be make a system error."

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\M020utiWindows\Parameters
ServiceDll = "%System%\Winds.dll"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\M020utiWindows
Type = "12"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = "{random characters}"

(Note: The default value data of the said registry entry is {random values}.)

Dropping Routine

This backdoor drops the following files:

  • %System%\Winds.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This backdoor deletes itself after execution.

This report is generated via an automated analysis 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

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\M020utiWindows
    • Parameters
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo

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_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\M020utiWindows
    • Load_Path = "{malware path and file name}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\M020utiWindows
    • ConnectGroup = "Default"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\M020utiWindows
    • Description = "Microsoft Device Manager,Stop service will be make a system error."
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\M020utiWindows\Parameters
    • ServiceDll = "%System%\Winds.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\M020utiWindows
    • Type = "12"

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
    • From: netsvcs = "{random characters}"
      To: netsvcs = ""{random values}""

Step 6

Search and delete this file

[ 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.
  • %System%\Winds.dll

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZEGOST.HJH. 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 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • G®‰


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