WORM_DORKBOT.TOM
Worm:Win32/Dorkbot.I (Microsoft); Win32/Dorkbot.B worm (NOD32); BDS/Dorkbot.hrjvwa (AntiVir); W32/Dorkbot.GV (exact) (F-Prot); Worm.Win32.Dorkbot (Ikarus);
Windows
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.
It deletes itself after execution.
TECHNICAL DETAILS
131,584 bytes
EXE
Yes
04 Oct 2014
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.
Installation
This worm drops the following copies of itself into the affected system:
- %Application Data%\temp.bin
- %Application Data%\ScreenSaverPro.scr
- %Application Data%\Microsoft\{random filename 1}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
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
Screen Saver Pro 3.1 = "%Application Data%\ScreenSaverPro.scr"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random filename 1} = "%Application Data%\Microsoft\{random filename 1}.exe"
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Recent File List
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Settings
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\View
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Text
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Colors
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\General-Summary
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://ie.{BLOCKED}lear.com"
(Note: The default value data of the said registry entry is http://www.microsoft.com/.)
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- {removable drive letter}:\{random filename}.exe
Other Details
This worm connects to the following possibly malicious URL:
- http://api.{BLOCKED}ia.com
It deletes itself after execution.
NOTES:
It creates shortcut files (.LNK) that use the names of the folders/files located on the removable drives for their file names. It then sets the attributes of the original folders/files to Hidden and System to trick users into clicking the .LNK files.
SOLUTION
9.700
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Restart in Safe Mode
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\Microsoft\Windows\CurrentVersion
- Applets
- Applets
Step 5
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
- Screen Saver Pro 3.1 = "%Application Data%\ScreenSaverPro.scr"
- Screen Saver Pro 3.1 = "%Application Data%\ScreenSaverPro.scr"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random filename 1} = "%Application Data%\Microsoft\{random filename 1}.exe"
- {random filename 1} = "%Application Data%\Microsoft\{random filename 1}.exe"
Step 6
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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- From: Start Page = http://ie.{BLOCKED}lear.com
To: Start Page = http://www.microsoft.com/
- From: Start Page = http://ie.{BLOCKED}lear.com
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.TOM. 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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