Content
Vundo
- Type
- Trojan
- SubType
- Win32
- Discovery Date
- 08/20/2004
- Length
- Varies
- Minimum DAT
- 4388 (08/25/2004)
- Updated DAT
- 5663 (07/01/2009)
- Minimum Engine
- 5.1.00
- Description Added
- 08/20/2004
- Description Modified
- 04/06/2006 7:30 PM (PT)
Tab Navigation
Characteristics
[Update 04/06/2006]
The latest variants of this trojan are observed to display fake error messages and asks the user to download security software programs. User will be asked to download SysProtect application to remove the threat.
Registry changes
Vundo maintains most of the original characterstics, few of the registry changes are mentioned below.
Add itself as a BHO.
- HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{1AE6D7D5-0C28-4DB6-9FD1-33B870A4C5F2}\InprocServer32\: "path to the trojan DLL file"
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{1AE6D7D5-0C28-4DB6-9FD1-33B870A4C5F2}
Create a winlogon key with random filename.
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\filename.
\Startup: "SysLogon"
\Logoff: "SysLogoff"
The following keys are also added.
- HKEY_LOCAL_MACHINE\SOFTWARE\Classes\DosSpecFolder.DosSpecFolder
- HKEY_LOCAL_MACHINE\SOFTWARE\Classes\DosSpecFolder.DosSpecFolder.1
------------------------------------
Older variants bears the following characteristics:
- decrypts and drops a DLL file to the victim machine. The DLL appears to be intended to harvest data from the victim machine.
- drops a second EXE to the victim machine. This component appears to be related to Adware-Virtumundo .
Upon execution, VMTEMP.TMP is written to the local temporary directory, for example:
- C:\DOCUMENTS AND SETTINGS\USER\LOCAL
SETTINGS\TEMP\VMTEMP.TMP (387,133 bytes)
When this file is executed the following Registry key is added:
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\RunOnce "*(filename)"
Two DLLs are also installed to the victim machine, both 86,016 bytes in size. The filename used is random, but a .DAT file extension is used. For example:
- TMW.DAT (86,016 bytes)
The following CLSIDs are added for these DLLs:
- HKEY_CLASSES_ROOT\CLSID\
{8109AF33-6949-4833-8881-43DCC232B7B2} - HKEY_CLASSES_ROOT\CLSID\
{2316230A-C89C-4BCC-95C2-66659AC7A775}
The DLLs may be installed as Browser Helper Objects (BHOs) on the victim machine via the following keys:
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Explorer\Browser Helper Objects\
{8109AF33-6949-4833-8881-43DCC232B7B2} - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Explorer\Browser Helper Objects\
{2316230A-C89C-4BCC-95C2-66659AC7A775}
The following keys are also added:
- HKEY_CLASSES_ROOT\ATLEvents.ATLEvents
- HKEY_CLASSES_ROOT\ATLEvents.ATLEvents.1
Various data is then sent to a remote server (via HTTP). This includes:
- version information
- crash history
- affiliate ID
One of the DLLs (actually uses .DAT file extension) is loaded within the legitimate EXPLORER.EXE process, which may lead to misleading alerts from any software firewall when the remote connections are initiated.
Symptoms
- Existence of Registry keys details above.
- Outgoing traffic to following remote server:
- virtumonde.com
- Newer variants display fake error screen asking the user to download rouge system security tools.
Method of Infection
Trojans do not self-replicate. They are spread manually, often under the premise that the executable is something beneficial. Distribution channels include IRC, peer-to-peer networks, newsgroup postings, etc
Removal
Certain variants of the Vundo trojan are especially difficult to remove. Current DAT and Engine functionality does not yet provide an automatic method to fully remove this threat if it is active in memory. However, a combination of manual and DAT/Engine removal methods does allow for successful removal of this threat.
Instructions
- Download Process Explorer (procexp.exe) from Sysinternals
- Reboot the infected machine
- Launch the VirusScan On-Demand Scanner (ODS), or the command-line scanner, but don't initiate the scan yet
- Run Process Explorer and suspend the Explorer.exe, Winlogon.exe, and rundll32.exe processes (right-click on these process names and choose suspend)
- Scan & clean with the current DAT files and engine (the Window launched in step 3 above) [there will be clean failures, that is expected]
- Physically power the machine off and back on.(a hard reset is required as Windows will not shutdown without Winlogon.exe running, and resuming that process will revert the changes made by the scanner).
These steps will removal all relevant registry entries and identified Vundo components.
Variants
Variants
N/A
All Information
Overview -
This is a trojan detection. Unlike viruses, trojans do not self-replicate. They are spread manually, often under the premise that they are beneficial or wanted. The most common installation methods involve system or security exploitation, and unsuspecting users manually executing unknown programs. Distribution channels include email, malicious or hacked web pages, Internet Relay Chat (IRC), peer-to-peer networks, etc.
Aliases
- Adware.VirtuMonde (Symantec)
- Troj/AgentSpy-A (Sophos)
- Trojan.Vundo.B (Symantec)
Characteristics
Characteristics -
[Update 04/06/2006]
The latest variants of this trojan are observed to display fake error messages and asks the user to download security software programs. User will be asked to download SysProtect application to remove the threat.
Registry changes
Vundo maintains most of the original characterstics, few of the registry changes are mentioned below.
Add itself as a BHO.
- HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{1AE6D7D5-0C28-4DB6-9FD1-33B870A4C5F2}\InprocServer32\: "path to the trojan DLL file"
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{1AE6D7D5-0C28-4DB6-9FD1-33B870A4C5F2}
Create a winlogon key with random filename.
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\filename.
\Startup: "SysLogon"
\Logoff: "SysLogoff"
The following keys are also added.
- HKEY_LOCAL_MACHINE\SOFTWARE\Classes\DosSpecFolder.DosSpecFolder
- HKEY_LOCAL_MACHINE\SOFTWARE\Classes\DosSpecFolder.DosSpecFolder.1
------------------------------------
Older variants bears the following characteristics:
- decrypts and drops a DLL file to the victim machine. The DLL appears to be intended to harvest data from the victim machine.
- drops a second EXE to the victim machine. This component appears to be related to Adware-Virtumundo .
Upon execution, VMTEMP.TMP is written to the local temporary directory, for example:
- C:\DOCUMENTS AND SETTINGS\USER\LOCAL
SETTINGS\TEMP\VMTEMP.TMP (387,133 bytes)
When this file is executed the following Registry key is added:
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\RunOnce "*(filename)"
Two DLLs are also installed to the victim machine, both 86,016 bytes in size. The filename used is random, but a .DAT file extension is used. For example:
- TMW.DAT (86,016 bytes)
The following CLSIDs are added for these DLLs:
- HKEY_CLASSES_ROOT\CLSID\
{8109AF33-6949-4833-8881-43DCC232B7B2} - HKEY_CLASSES_ROOT\CLSID\
{2316230A-C89C-4BCC-95C2-66659AC7A775}
The DLLs may be installed as Browser Helper Objects (BHOs) on the victim machine via the following keys:
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Explorer\Browser Helper Objects\
{8109AF33-6949-4833-8881-43DCC232B7B2} - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Explorer\Browser Helper Objects\
{2316230A-C89C-4BCC-95C2-66659AC7A775}
The following keys are also added:
- HKEY_CLASSES_ROOT\ATLEvents.ATLEvents
- HKEY_CLASSES_ROOT\ATLEvents.ATLEvents.1
Various data is then sent to a remote server (via HTTP). This includes:
- version information
- crash history
- affiliate ID
One of the DLLs (actually uses .DAT file extension) is loaded within the legitimate EXPLORER.EXE process, which may lead to misleading alerts from any software firewall when the remote connections are initiated.
Symptoms
Symptoms -
- Existence of Registry keys details above.
- Outgoing traffic to following remote server:
- virtumonde.com
- Newer variants display fake error screen asking the user to download rouge system security tools.
Method of Infection
Method of Infection -
Trojans do not self-replicate. They are spread manually, often under the premise that the executable is something beneficial. Distribution channels include IRC, peer-to-peer networks, newsgroup postings, etc
Removal -
Removal -
Certain variants of the Vundo trojan are especially difficult to remove. Current DAT and Engine functionality does not yet provide an automatic method to fully remove this threat if it is active in memory. However, a combination of manual and DAT/Engine removal methods does allow for successful removal of this threat.
Instructions
- Download Process Explorer (procexp.exe) from Sysinternals
- Reboot the infected machine
- Launch the VirusScan On-Demand Scanner (ODS), or the command-line scanner, but don't initiate the scan yet
- Run Process Explorer and suspend the Explorer.exe, Winlogon.exe, and rundll32.exe processes (right-click on these process names and choose suspend)
- Scan & clean with the current DAT files and engine (the Window launched in step 3 above) [there will be clean failures, that is expected]
- Physically power the machine off and back on.(a hard reset is required as Windows will not shutdown without Winlogon.exe running, and resuming that process will revert the changes made by the scanner).
These steps will removal all relevant registry entries and identified Vundo components.
Additional Windows ME/XP removal considerations
Variants
Variants -
N/A
