BKDR_CIADOOR.S
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)
Windows 2000, Windows XP, Windows Server 2003

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
183,506 bytes
EXE
Yes
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
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
Step 3
Enable Registry Editor, Task Manager, and Folder options
Step 4
Delete this registry key
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
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
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""
- From: Start = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Nla
- From: Start = "0"
To: Start = ""3""
- From: Start = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\SENS
- From: Start = "0"
To: Start = ""2""
- From: Start = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SENS
- From: Start = "0"
To: Start = ""2""
- From: Start = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\SharedAccess
- From: Start = "0"
To: Start = ""2""
- From: Start = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess
- From: Start = "0"
To: Start = ""2""
- From: Start = "0"
Step 7
Search and delete these components
- %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}
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