BKDR_CIADOOR.S


 ALIASES:

Backdoor:Win32/Ciadoor.C (Microsoft); BackDoor-ASB.gen (McAfee); Backdoor.Ciadoor (Symantec); Backdoor.Win32.Ciadoor.cdt, Backdoor.Win32.Ciadoor.cdt (Kaspersky); Backdoor.Ciadoor (Sunbelt); DeepScan:Generic.Malware.SLMDBCbg.22FB442E (FSecure)

 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 disables Task Manager, Registry Editor, and Folder Options.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

183,506 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Sep 2012

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Generic Host Process = "%System%\scvhost.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
set\set

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows\
Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\
Services\Nla

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\
Services\SENS

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\
Services\SharedAccess

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
set\set
set = "UbH683e69c.ini"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Generic Host Process = "%System%\scvhost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows\
Run
Generic Host Process = "%System%\scvhost.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\
Services\Nla
Start = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\
Services\SENS
Start = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\
Services\SharedAccess
Start = "0"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\
Services\Nla
Start = "0"

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

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Nla
Start = "0"

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

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\
Services\SENS
Start = "0"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SENS
Start = "0"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\
Services\SharedAccess
Start = "0"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess
Start = "0"

(Note: The default value data of the said registry entry is 2.)

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{E14DCE67-8FB7-4721-8149-179BAA4D792C}

Dropping Routine

This backdoor drops the following files:

  • %System%\UbH683e69c.ini
  • %System%\del32.bat
  • %System%\scvhost.exe

(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:

9.200

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

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

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.

  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings
    • set
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • System
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services
    • Nla
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services
    • SENS
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services
    • SharedAccess

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\CurrentVersion\Run
    • Generic Host Process = "%System%\scvhost.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\set\set
    • set = "UbH683e69c.ini"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • Generic Host Process = "%System%\scvhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows\Run
    • Generic Host Process = "%System%\scvhost.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\Nla
    • Start = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\SENS
    • Start = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\SharedAccess
    • Start = "0"

Step 6

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\SYSTEM\ControlSet002\Services\Nla
    • From: Start = "0"
      To: Start = ""3""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Nla
    • From: Start = "0"
      To: Start = ""3""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\SENS
    • From: Start = "0"
      To: Start = ""2""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SENS
    • From: Start = "0"
      To: Start = ""2""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\SharedAccess
    • From: Start = "0"
      To: Start = ""2""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess
    • From: Start = "0"
      To: Start = ""2""

Step 7

Search and delete these components

[ Learn More ]
There may be some components 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%\UbH683e69c.ini
  • %System%\del32.bat
  • %System%\scvhost.exe

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_CIADOOR.S. 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 9

Restore these deleted registry keys/values from backup

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

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {E14DCE67-8FB7-4721-8149-179BAA4D792C}


Did this description help? Tell us how we did.