BKDR_ETUMBOT.AKV
Backdoor:Win32/Etumbot.gen(Microsoft), Backdoor.Win32.Farfli(Ikarus)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It does not have any propagation routine.
It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.
It connects to certain websites to send and receive information.
TECHNICAL DETAILS
Arrival Details
This backdoor 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 backdoor drops the following files:
- %User Temp%\~DF4E74.doc
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It drops and executes the following files:
- %Application Data%\Microsoft\Windows\WindowsUpdate.exe - detected as BKDR_ETUMBOT.AKV
(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 backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
WindowsUpdate = "%Application Data%\Microsoft\Windows\WindowsUpdate.exe"
Propagation
This backdoor does not have any propagation routine.
Backdoor Routine
This backdoor executes the following command(s) from a remote malicious user:
- Perform Remote Shell
- Download Files
- Upload Files
- Execute Files
- Sleep
Information Theft
This backdoor gathers the following data:
- User Name
- Computer Name
- IP Address
- OS Version
- Proxy Server
Other Details
This backdoor connects to the following website to send and receive information:
- http://{BLOCKED}.{BLOCKED}.46.102:443/XEL{random digits}={random digits}.cgi?{Encrypted Information}
It opens the following files:
- %User Temp%\~DF4E74.doc
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
NOTES:
Where {Encrypted Information} contains encrypted User Name, Host Name, IP Address, OS Version, and Proxy Server.
SOLUTION
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
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
- WindowsUpdate = "%Application Data%\Microsoft\Windows\WindowsUpdate.exe"
- WindowsUpdate = "%Application Data%\Microsoft\Windows\WindowsUpdate.exe"
Step 4
Search and delete this file
- %User Temp%\~DF4E74.doc
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ETUMBOT.AKV. 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.
Did this description help? Tell us how we did.