TROJ_AGENT_036496.TOMB
Backdoor:Win32/Fynloski.A (Microsoft); Generic BackDoor.yl (McAfee); Downloader (Symantec); PAK:MPRESS, Backdoor.Win32.Delf.aekf (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); GenPack:Trojan.Generic.KDV.584379 (FSecure)
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
337,920 bytes
EXE
Yes
25 Jun 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.
Installation
This Trojan drops the following copies of itself into the affected system:
- %Start Menu%\MSDCSC\msdcsc.exe
(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)
It creates the following folders:
- %Start Menu%\MSDCSC
(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)
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
MicroUpdate = "%Start Menu%\MSDCSC\msdcsc.exe"
It 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,%Start Menu%\MSDCSC\msdcsc.exe"
(Note: The default value data of the said registry entry is %Windows%\system32\userinit.exe,.)
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\DC3_FEXEC
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
CurrentVersion
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
CurrentVersion\Explorern
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
CurrentVersion\Explorern
NoControlPanel = "1"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wscsvc
Start = "4"
(Note: The default value data of the said registry entry is 2.)
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
Identify and delete files detected as TROJ_AGENT_036496.TOMB using either the Startup Disk or Recovery Console
Step 3
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
- DC3_FEXEC
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- System
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\policies
- CurrentVersion
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\CurrentVersion
- Explorern
Step 4
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
- MicroUpdate = "%Start Menu%\MSDCSC\msdcsc.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
- EnableLUA = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\CurrentVersion\Explorern
- NoControlPanel = "1"
Step 5
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\Security Center
- AntiVirusDisableNotify = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- UpdatesDisableNotify = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wscsvc
- From: Start = "4"
To: Start = ""2""
- From: Start = "4"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: UserInit = "%System%\userinit.exe,%Start Menu%\MSDCSC\msdcsc.exe"
To: UserInit = ""%Windows%\system32\userinit.exe,""
- From: UserInit = "%System%\userinit.exe,%Start Menu%\MSDCSC\msdcsc.exe"
Step 6
Search and delete this folder
- %Start Menu%\MSDCSC
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT_036496.TOMB. 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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