WORM_AINSLOT.A
Worm:Win32/Ainslot.A (Microsoft)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Propagates via removable drives
This worm arrives via removable drives. It may be downloaded by other malware/grayware/spyware from remote sites. It may be dropped by other malware.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It logs a user's keystrokes to steal information.
TECHNICAL DETAILS
249,856 bytes
EXE
Yes
08 Apr 2011
Drops files, Steals information
Arrival Details
This worm arrives via removable drives.
It may be downloaded by other malware/grayware/spyware from remote sites.
It may be dropped by other malware.
Installation
This worm drops the following copies of itself into the affected system:
- %User Profile%\Application Data\Z5Y4JH2LYO.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Active Setup\Installed Components\{D8CCCFA7-16D2-EFEC-FDECB77E2836}
StubPath = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{D8CCCFA7-16D2-EFEC-FDECB77E2836}
StubPath = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run
Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\Software\VB and VBA Program Settings
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UACDisableNotify = 0
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = 0
HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE
LLCTFVD8U1 = "{date of first execution}"
HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID
LLCTFVD8U1 = "graig's Bot"
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorzedApplications\
List
{malware path and file name} = "{malware path and file name}:*:Enabled:Windows Messanger"
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- {removable drive letter}:\{malware file name}.exe
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}.exe
Dropping Routine
This worm drops the following file(s), which it uses for its keylogging routine:
- %User Profile%\Application Data\data.dat
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Information Theft
This worm logs a user's keystrokes to steal information.
NOTES:
It sends the stolen information to the following URL:
- {BLOCKED}ine.no-ip.biz:81
However, as of this writing, the said URL is inaccessible.
SOLUTION
8.900
7.958.03
08 Apr 2011
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
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Active Setup\Installed Components\{D8CCCFA7-16D2-EFEC-FDECB77E2836}
- StubPath = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- StubPath = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{D8CCCFA7-16D2-EFEC-FDECB77E2836}
- StubPath = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- StubPath = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\run
- Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- Windows Defender = "%User Profile%\Application Data\Z5Y4JH2LYO.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- UACDisableNotify = 0
- UACDisableNotify = 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
- EnableLUA = 0
- EnableLUA = 0
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorzedApplications\List
- {malware path and file name} = "{malware path and file name}:*:Enabled:Windows Messanger"
- {malware path and file name} = "{malware path and file name}:*:Enabled:Windows Messanger"
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_CURRENT_USER\Software
- VB and VBA Program Settings
- VB and VBA Program Settings
Step 5
Search and delete AUTORUN.INF files created by WORM_AINSLOT.A that contain these strings
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_AINSLOT.A. 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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