WORM_DELF.QAY
Windows 2000, XP, Server 2003

Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Propagates via removable drives
This worm drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
TECHNICAL DETAILS
129,024 bytes
PE
Yes
27 May 2010
Installation
This worm drops the following copies of itself into the affected system:
- %System%\logo.scr
- %System%\drivers\smss.exe
- %System%\drivers\Cache\New.scr
- %System%\drivers\Cache\Bckp.trj
(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.)
It creates the following folders:
- %System%\drivers\Cache
(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.)
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
NvCplDeamon = %System%\drivers\smss.exe
Other System Modifications
This worm adds the following registry entries:
HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE = %System%\logo.scr
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
NoFolderoptions = 1
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanserver\Shares
!Film = {hex value}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanserver\Shares\
Security
!Film = {hex value}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = 1
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DoNotAllowExceptions = 0
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
enableFirewall = 0
It modifies the following registry entries:
HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveTimeOut = 100
(Note: The default value data of the said registry entry is 0.)
HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveActive = 1
(Note: The default value data of the said registry entry is 0.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 0
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = 1
(Note: The default value data of the said registry entry is 0.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0
(Note: The default value data of the said registry entry is 1.)
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot
Propagation
This worm drops copies of itself in all removable drives.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[AutoRun]
open={malware file name}.scr
shell\Open\command={malware file name}.scr
SOLUTION
8.900
7.202.10
27 May 2010
5/27/2010 12:00:00 AM
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 WORM_DELF.QAY using either the Startup Disk or Recovery Console
Step 3
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\Microsoft\Windows\CurrentVersion\Run
- NvCplDeamon = %System%\drivers\smss.exe
- NvCplDeamon = %System%\drivers\smss.exe
- In HKEY_CURRENT_USER\Control Panel\Desktop
- SCRNSAVE.EXE = %System%\logo.scr
- SCRNSAVE.EXE = %System%\logo.scr
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- FirewallOverride = 1
- FirewallOverride = 1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- FirewallDisableNotify = 1
- FirewallDisableNotify = 1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer
- NoFolderoptions = 1
- NoFolderoptions = 1
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Shares
- !Film = {hex value}
- !Film = {hex value}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Shares\Security
- !Film = {hex value}
- !Film = {hex value}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- DisableNotifications = 1
- DisableNotifications = 1
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- DoNotAllowExceptions = 0
- DoNotAllowExceptions = 0
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- enableFirewall = 0
- enableFirewall = 0
Step 4
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_CURRENT_USER\Control Panel\Desktop
- From: ScreenSaveTimeOut = 100
To: 0
- From: ScreenSaveTimeOut = 100
- In HKEY_CURRENT_USER\Control Panel\Desktop
- From: ScreenSaveActive = 1
To: 0
- From: ScreenSaveActive = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = 0
To: 1
- From: Hidden = 0
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = 1
To: 0
- From: HideFileExt = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = 0
To: 1
- From: ShowSuperHidden = 0
Step 5
Restoring Deleted Registry Keys
- Still in Registry Editor, in the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
Control>SafeBoot>Minimal - Right-click on the key and choose New>Key. Change the value of the new key to:
{4D36E967-E325-11CE-BFC1-08002BE10318} - Right-click on the value name and choose Modify. Change the value data of this entry to:
DiskDrive - In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
Control>SafeBoot>Network - Right-click on the key and choose New>Key. Change the value of the new key to:
{4D36E967-E325-11CE-BFC1-08002BE10318} - Right-click on the value name and choose Modify. Change the value data of this entry to:
DiskDrive - Close Registry Editor.
Step 6
Search and delete this folder
- %System%\drivers\Cache
Step 7
Search and delete AUTORUN.INF files created by WORM_DELF.QAY that contain these strings
[AutoRun]
open={malware file name}.scr
shell\Open\command={malware file name}.scr
Step 8
Scan your computer with your Trend Micro product to delete files detected as WORM_DELF.QAY. 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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