TROJ_VILSEL.GR

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.

File Size: 1,544,195 bytes

File Type: EXE

Memory Resident: Yes

Initial Samples Received Date: 24 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.

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
SusClientdetonador = "%System%\exploids.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
SusClientdetonador2 = "%System%\exploidwin.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\MRT

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UACDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AutoUpdateDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
InternetSettingsDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
UACDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
AntiVirusDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
AntiVirusOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
FirewallOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
UpdatesDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
UpdatesOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\MRT
DontReportInfectionInformation = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = ".exe;.bat;.com;.cmd;"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
RunInvalidSignatures = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
%System%\exploids.exe = "NoAsInvoker"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
%System%\explodwin.exe = "NoAsInvoker"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirstRunDisabled = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
CheckExeSignatures = "no"

(Note: The default value data of the said registry entry is yes.)

Dropping Routine

This Trojan drops the following files:

%System%\exploids.exe
%System%\exploidwin.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.)

This report is generated via an automated analysis system.

Minimum Scan Engine: 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

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

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
- Svc

In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft
- Windows Defender

In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft
- MRT

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- Associations

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- Attachments

In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags
- Layers

Step 4

Delete this registry value

[ Learn More ]

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
- SusClientdetonador = "%System%\exploids.exe"

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- SusClientdetonador2 = "%System%\exploidwin.exe"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- UACDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- AutoUpdateDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- InternetSettingsDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- UpdatesOverride = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- UACDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- AntiVirusDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- FirewallDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- AntiVirusOverride = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- FirewallOverride = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- UpdatesDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
- UpdatesOverride = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
- DisableAntiSpyware = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\MRT
- DontReportInfectionInformation = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
- EnableLUA = "0"

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Associations
- LowRiskFileTypes = ".exe;.bat;.com;.cmd;"

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments
- SaveZoneInformation = "1"

In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Download
- RunInvalidSignatures = "1"

In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
- %System%\exploids.exe = "NoAsInvoker"

In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
- %System%\explodwin.exe = "NoAsInvoker"

To delete the registry value this malware/grayware created:

Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run
In the right panel, locate and delete the entry:
SusClientdetonador = "%System%\exploids.exe"
Again In the right panel, locate and delete the entry:
SusClientdetonador2 = "%System%\exploidwin.exe"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Security Center
In the right panel, locate and delete the entry:
UACDisableNotify = "1"
Again In the right panel, locate and delete the entry:
AutoUpdateDisableNotify = "1"
Again In the right panel, locate and delete the entry:
InternetSettingsDisableNotify = "1"
Again In the right panel, locate and delete the entry:
UpdatesOverride = "1"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Security Center>Svc
In the right panel, locate and delete the entry:
UACDisableNotify = "1"
Again In the right panel, locate and delete the entry:
AntiVirusDisableNotify = "1"
Again In the right panel, locate and delete the entry:
FirewallDisableNotify = "1"
Again In the right panel, locate and delete the entry:
AntiVirusOverride = "1"
Again In the right panel, locate and delete the entry:
FirewallOverride = "1"
Again In the right panel, locate and delete the entry:
UpdatesDisableNotify = "1"
Again In the right panel, locate and delete the entry:
UpdatesOverride = "1"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Policies>Microsoft>Windows Defender
In the right panel, locate and delete the entry:
DisableAntiSpyware = "1"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Policies>Microsoft>MRT
In the right panel, locate and delete the entry:
DontReportInfectionInformation = "1"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>policies>system
In the right panel, locate and delete the entry:
EnableLUA = "0"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Policies>Associations
In the right panel, locate and delete the entry:
LowRiskFileTypes = ".exe;.bat;.com;.cmd;"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Policies>Attachments
In the right panel, locate and delete the entry:
SaveZoneInformation = "1"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Internet Explorer>Download
In the right panel, locate and delete the entry:
RunInvalidSignatures = "1"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows NT>CurrentVersion>AppCompatFlags>Layers
In the right panel, locate and delete the entry:
%System%\exploids.exe = "NoAsInvoker"
Again In the right panel, locate and delete the entry:
%System%\explodwin.exe = "NoAsInvoker"
Close Registry Editor.

Step 5

Restore this modified registry value

[ Learn More ]

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
- From: FirstRunDisabled = "1"
  To: FirstRunDisabled = ""1""

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- AntiVirusDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- AntiVirusOverride = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- FirewallDisableNotify = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- FirewallOverride = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- UpdatesDisableNotify = "1"

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = "2"
  To: Hidden = ""2""

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = "1"
  To: HideFileExt = ""1""

In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Download
- From: CheckExeSignatures = "no"
  To: CheckExeSignatures = ""yes""

Step 6

Search and delete these files

[ Learn More ]

There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.

%System%\exploids.exe
%System%\exploidwin.exe

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VILSEL.GR. 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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