WORM_AUTORUN.ENI
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It does not have any backdoor routine.
It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats. As of this writing, the said sites are inaccessible.
It does not have any information-stealing capability.
TECHNICAL DETAILS
Arrival Details
This worm arrives via removable drives.
It 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 worm drops the following copies of itself into the affected system and executes them:
- %System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It drops the following non-malicious file:
- %System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Desktop.ini
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:
- %System Root%\Recycle
- %System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It injects itself into the following processes as part of its memory residency routine:
- explorer.exe
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}
StubPath = "%System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe"
Other System Modifications
This worm adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}
Propagation
This worm creates the following folders in all removable drives:
- {Drive Letter}:\Recycle
- {Drive Letter}:\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341
It drops the following copy(ies) of itself in all removable drives:
- {Drive Letter}:\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.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=Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
shell\open\default=1
Backdoor Routine
This worm does not have any backdoor routine.
Download Routine
This worm connects to the following malicious URLs:
- http://www.{BLOCKED}zy.com
As of this writing, the said sites are inaccessible.
Information Theft
This worm does not have any information-stealing capability.
NOTES:
Other Details
This worm does not have rootkit capabilities.
This worm does not exploit any vulnerability.
SOLUTION
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 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
- {28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}
- {28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}
Step 4
Search and delete these folders
- %System Root%\Recycle
- {Drive Letter}:\Recycle
Step 5
Search and delete AUTORUN.INF files created by WORM_AUTORUN.ENI that contain these strings
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_AUTORUN.ENI. 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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