TROJ_MATSNU.AO
Trojan:Win32/Matsnu.gen!A (Microsoft); Generic BackDoor.u (McAfee); Backdoor.Matsnu (Symantec); Trojan-Dropper.Win32.Injector.dijb (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.KDV.568768 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
It deletes itself after execution.
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 drops the following copies of itself into the affected system:
- %System%\{random filename}.exe
- %User Temp%\{random filename}.exe
(Note: %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.. %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.)
It creates the following folders:
- %Program Files%\Trusteer
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
Autostart Technique
This Trojan modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
userinit = "%System%\userinit.exe,%System%\{random file name}.exe,"
(Note: The default value data of the said registry entry is %Windows%\system32\userinit.exe,.)
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\RapportMgmtService
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RapportCerberus_29574
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RapportEI
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RapportKELL
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RapportPG
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CLASSES_ROOT\.eze
HKEY_CLASSES_ROOT\MyEze.1
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportSetup-Full.exe
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportSetup.exe
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportMgmtService.exe
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportService.exe
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportSetup-Full.exe
Debugger = "RPXService.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportSetup.exe
Debugger = "RPXService.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportMgmtService.exe
Debugger = "RPService.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportService.exe
Debugger = "RPService.exe"
Dropping Routine
This Trojan drops the following files:
- %Windows%\RPService.exe
- %Program Files%\Trusteer\Rapport\bin\RapportService.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %Program Files% is the default Program Files folder, usually C:\Program Files.)
Other Details
This Trojan deletes itself after execution.
SOLUTION
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
Identify and delete files detected as TROJ_MATSNU.AO using either the Startup Disk or Recovery Console
Step 3
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\Winlogon
- From: userinit = "%System%\userinit.exe,%System%\{random filename}.exe,"
To: userinit = "%System%\userinit.exe,"
- From: userinit = "%System%\userinit.exe,%System%\{random filename}.exe,"
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
- RapportKELL
- RapportKELL
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RapportPG
- RapportPG
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RapportMgmtService
- RapportMgmtService
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RapportCerberus_29574
- RapportCerberus_29574
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RapportEI
- RapportEI
- In HKEY_CLASSES_ROOT
- .eze
- .eze
- In HKEY_CLASSES_ROOT
- MyEze.1
- MyEze.1
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- RapportSetup-Full.exe
- RapportSetup-Full.exe
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- RapportSetup.exe
- RapportSetup.exe
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- RapportMgmtService.exe
- RapportMgmtService.exe
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- RapportService.exe
- RapportService.exe
Step 5
Search and delete these files
- %Windows%\RPService.exe
Step 6
Search and delete these folders
- %Program Files%\Trusteer
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_MATSNU.AO. 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.
Did this description help? Tell us how we did.