WORM_RONTKBR.F
Worm:Win32/Brontok.BU@mm (Microsoft)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives by connecting affected removable drives to a system. 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 uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.
It disables Task Manager, Registry Editor, and Folder Options.
It drops copies of itself into all the removable drives connected to an affected system.
TECHNICAL DETAILS
Varies
EXE
Yes
17 Jul 2009
Arrival Details
This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It arrives by connecting affected removable drives to a system.
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:
- %Application Data%\csrss.exe
- %Application Data%\inetinfo.exe
- %Application Data%\lsass.exe
- %Application Data%\services.exe
- %Application Data%\smss.exe
- %System%\{user name}'S SETTING.SCR
- %User Profile%\TEMPLATES\Brengkolang.com
- %Windows%\eksplorasi.exe
- %Windows%\SHELLNEW\semaplong.exe
It uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.
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
Tok-Cirrhatus = "%Application Data%\{random}.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Bron-Spizaetus = "%Windows%\ShellNew\sempalong.exe"
It 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 %Windows%\sembako-{random}"
(Note: The default value data of the said registry entry is "Explorer.exe".)
It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\Empty.pif – copy of itself
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
Other System Modifications
This worm modifies the following file(s):
- %System Root%\AUTOEXEC.BAT
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It modifies the following registry entries:
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 creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableCMD = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"
Propagation
This worm drops copies of itself into all the removable drives connected to an affected system.
Other Details
This worm connects to the following possibly malicious URL:
- http://www.geocities.com/{BLOCKED}2/{BLOCKED}PDZROX.txt
- http://www.geocities.com/{BLOCKED}2/{BLOCKED}2.txt
SOLUTION
9.200
4.610.01
17 Jul 2009
4.611.00
17 Jul 2009
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
Terminate a malware/grayware process
*Note: If the detected process is not displayed in theWindows Task Manager, continue doing the next steps.
- %Application Data%\csrss.exe
- %Application Data%\inetinfo.exe
- %Application Data%\lsass.exe
- %Application Data%\services.exe
- %Application Data%\smss.exe
- %Application Data%\winlogon.exe
- %System%\{user name}'S SETTING.SCR
- %User Profile%\TEMPLATES\Brengkolang.com
- %Windows%\eksplorasi.exe
- %Windows%\SHELLNEW\sempalong.exe
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
- Bron-Spizaetus = ""%windows%\ShellNew\sempalong.exe""
- Bron-Spizaetus = ""%windows%\ShellNew\sempalong.exe""
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Tok-Cirrhatus = ""%Application Data%\smss.exe""
- Tok-Cirrhatus = ""%Application Data%\smss.exe""
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
- DisableRegistryTools = 1
- DisableRegistryTools = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
- DisableCMD = 0
- DisableCMD = 0
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
- NoFolderOptions = 1
- NoFolderOptions = 1
Step 4
Restore this modified registry value
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\Windows NT\CurrentVersion\Winlogon
- From: Shell = "Explorer.exe %Windows%\eksplorasi.exe"
To: Shell = "Explorer.exe"
- From: Shell = "Explorer.exe %Windows%\eksplorasi.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = "0"
To: Hidden = "1"
- From: Hidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = "1"
To: HideFileExt = "0"
- From: HideFileExt = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: "ShowSuperHidden" = "0"
To: "ShowSuperHidden" = "1"
- From: "ShowSuperHidden" = "0"
Step 5
To delete the added job file:
- Click on Start>Programs>Accessories>System Tools>Scheduled Tasks
- Double-click on a job file.
- Check if the malware path and file name is in the Run: box.
- If it does, delete the job file.
- Repeat step 2-4 for the remaining job files.
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_RONTKBR.F. 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 7
Restore deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %System Root%\AUTOEXEC.bat
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