TROJ_NEBULER.SMS
Trojan:Win32/Nebuler.Q (Microsoft), W32/NEBULER.DA!tr (Fortinet), Win32/Nebuler.DA (Eset),
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
Arrival Details
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This Trojan adds the following mutexes to ensure that only one of its copies runs at any one time:
- c14f7bg943
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
MSIDLL = "rundll32.exe %System%\msi{random three letters}32.dll,{random}"
Other System Modifications
This Trojan adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
{random}
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path}\{malware name} = "{malware path}\{malware name}:*:Enabled:1"
Dropping Routine
This Trojan drops the following files:
- %System%\msi{random three letters}32.dll - detected as TROJ_NEBULER.SMJ
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}nsle1.la.funpic.de/admin/index.php?q={random}
- http://{BLOCKED}ob.nl/admin/index.php?q={random}
- http://{BLOCKED}c.unas.cz/admin/index.php?q={random}
- http://{BLOCKED}m/upd.php?q={random}
- http://{BLOCKED}/upd.php?q={random}
However, as of this writing, the said sites are inaccessible.
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 2
Remove the malware/grayware file dropped/downloaded by TROJ_NEBULER.SMS
- TROJ_NEBULER.SMJ
Step 3
Scan your computer with your Trend Micro product and note files detected as TROJ_NEBULER.SMS
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
- {random}
- {random}
Step 6
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- MSIDLL = "rundll32.exe %System%\msi{random three letters}32.dll,{random}"
- MSIDLL = "rundll32.exe %System%\msi{random three letters}32.dll,{random}"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- {malware path}\{malware name} = "{malware path}\{malware name}:*:Enabled:1"
- {malware path}\{malware name} = "{malware path}\{malware name}:*:Enabled:1"
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_NEBULER.SMS. 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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