WORM_AUTORUN.RXK
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
172,032 bytes
EXE
Yes
06 Sep 2013
Arrival Details
This worm 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 worm modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe tcpip.exe"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This worm deletes the following files:
- %System%\taskmgr.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
JITDebug = "0"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\CA\Certificates\
FE622EA7B33CA46519AB39736A66B8F6E41FF157
Blob = "{random values}"
(Note: The default value data of the said registry entry is {random values}.)
Dropping Routine
This worm drops the following files:
- %System%\send.vbs
- %System Root%\taskmrg.exe
- %System%\db.dll
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
This report is generated via an automated analysis system.
SOLUTION
9.300
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Identify and delete files detected as WORM_AUTORUN.RXK using either the Startup Disk or Recovery Console
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.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows Script
- Settings
Step 4
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 Script\Settings
- JITDebug = "0"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\CA\Certificates\FE622EA7B33CA46519AB39736A66B8F6E41FF157
- From: Blob = "{random values}"
To: Blob = ""{random values}""
- From: Blob = "{random values}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = "Explorer.exe tcpip.exe"
To: Shell = ""Explorer.exe""
- From: Shell = "Explorer.exe tcpip.exe"
Step 6
Search and delete these components
- %System%\send.vbs
- %System Root%\taskmrg.exe
- %System%\db.dll
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.RXK. 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.
Step 8
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %System%\taskmgr.exe
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