TROJ_RUDLIN.AB
Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
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.
TECHNICAL DETAILS
189,295 bytes
EXE
Yes
24 Apr 2012
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.
Autostart Technique
This Trojan registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{405DA3F3-1769-073C-6381-CE663A7211B4}
It 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\enkuqxvw
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\enkuqxvw\Parameters
Other System Modifications
This Trojan deletes the following files:
- %User Temp%\nsb1.tmp
- %System%\mlhzjuzd.dll.bak
- %System%\lplswvcl.dll
- %System%\lplswvcl.dat.bak
- %System%\pkyfvclf.dll
- %System%\pkyfvclf.dat.bak
- %System%\wmmvmmfj.dll
- %System%\wmmvmmfj.dat.bak
- %System%\ecgqgjro.dll
- %System%\ecgqgjro.dat.bak
- %System%\jkmeelhk.dll
- %System%\jkmeelhk.dat.bak
- %System%\gjsozjjf.dll
- %System%\gjsozjjf.dat.bak
- %System%\koszmugh.dll
- %System%\koszmugh.dat.bak
- %System%\jxcmkxfo.dll
- %System%\jxcmkxfo.dat.bak
- %System%\zkwlojqc.dll
- %System%\zkwlojqc.dat.bak
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}\InprocServer32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Mokznbwb
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Mokznbwb\CLSID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}\ProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
ShellIconOverlayIdentifiers\Enhanced Storage
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}\InprocServer32
ThreadingModel = "Apartment"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
Description = "Helper for Microsoft Composite Battery"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
DisplayName = "Microsoft Composite Battery Helper"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw
Type = "2"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw\Parameters
ServiceDll = "%System%\mlhzjuzd.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\enkuqxvw\Parameters
ServiceMain = "DllRegisterServer"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
Version = "64"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
Flags = "1"
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}.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "0"
Dropping Routine
This Trojan drops the following files:
- %User Temp%\nsr2.tmp
- %System%\mlhzjuzd.dll
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
This report is generated via an automated analysis system.
SOLUTION
9.200
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Restart in Safe Mode
Step 3
Close all opened browser windows
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- enkuqxvw
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\enkuqxvw
- Parameters
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
- {405DA3F3-1769-073C-6381-CE663A7211B4}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
- InprocServer32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
- Mokznbwb
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Mokznbwb
- CLSID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
- ProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers
- Enhanced Storage
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\Classes\CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}\InprocServer32
- ThreadingModel = "Apartment"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- Description = "Helper for Microsoft Composite Battery"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- DisplayName = "Microsoft Composite Battery Helper"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- ObjectName = "LocalSystem"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- Start = "2"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw
- Type = "2"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw\Parameters
- ServiceDll = "%System%\mlhzjuzd.dll"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\enkuqxvw\Parameters
- ServiceMain = "DllRegisterServer"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
- Version = "64"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{405DA3F3-1769-073C-6381-CE663A7211B4}
- Flags = "1"
Step 6
Restore this modified 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 NT\CurrentVersion\SvcHost
- From: netsvcs = "{random characters}"
To: netsvcs = ""{random values}""
- From: netsvcs = "{random characters}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- DisableSR = "0"
Step 7
Search and delete these files
- %User Temp%\nsr2.tmp
- %System%\mlhzjuzd.dll
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_RUDLIN.AB. 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 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.
- %User Temp%\nsb1.tmp
- %System%\mlhzjuzd.dll.bak
- %System%\lplswvcl.dll
- %System%\lplswvcl.dat.bak
- %System%\pkyfvclf.dll
- %System%\pkyfvclf.dat.bak
- %System%\wmmvmmfj.dll
- %System%\wmmvmmfj.dat.bak
- %System%\ecgqgjro.dll
- %System%\ecgqgjro.dat.bak
- %System%\jkmeelhk.dll
- %System%\jkmeelhk.dat.bak
- %System%\gjsozjjf.dll
- %System%\gjsozjjf.dat.bak
- %System%\koszmugh.dll
- %System%\koszmugh.dat.bak
- %System%\jxcmkxfo.dll
- %System%\jxcmkxfo.dat.bak
- %System%\zkwlojqc.dll
- %System%\zkwlojqc.dat.bak
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