BKDR_RBOT.SMB
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This backdoor may be downloaded by other malware/grayware from remote sites.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
Arrival Details
This backdoor may be downloaded by the following malware/grayware from remote sites:
- WORM_SMALL.ECD
Installation
This backdoor drops the following files:
- %System%\{random}.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Autostart Technique
This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
ImagePath = "%system%\{random}.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
DisplayName = "Windows {random}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
Description = "Optical sensors monitor the atmosphere to detect the atmosphere of light and adjust the brightness of the display changes"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_{random}\
0000
Service = "{random}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_{random}\
0000
DeviceDesc = "Windows {random}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_{random}\
0000\Control
ActiveService = "{random}"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\{random}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_{random}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Eventlog\Application\
Service1
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_{random}\
0000
It adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\{random}\
DEBUG
Trace Level = ""
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Eventlog\Application\
Service1
EventMessageFile = "%WINDOWS%\Microsoft.NET\Framework\v2.0.50727\EventLogMessages.dll"
Other Details
This backdoor connects to the following possibly malicious URL:
- http://{BLOCKED}t.{BLOCKED}ca.com/it.asp?intTimes=0
It deletes the initially executed copy of itself
SOLUTION
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 3
Identify and terminate files detected as BKDR_RBOT.SMB
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 4
Restart in Safe Mode
Step 5
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_LOCAL_MACHINE\SOFTWARE\Microsoft\ESENT\Process\
- {random}
- {random}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\
- LEGACY_{random}
- LEGACY_{random}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
- {random}
- {random}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application\
- Service1
- Service1
Step 6
Search and delete this file
- %System%\{random}.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_RBOT.SMB. 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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