Arrival Details
This Backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
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 Backdoor drops the following copies of itself into the affected system:
- %User Profile%\Music\regdrv.exe
- %User Profile%\Videos\Regdriver.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista, 7, and 8.)
It drops the following files:
- %User Temp%\aspr_keys.ini ← (to be deleted afterward)
- %User Profile%\Music\aspr_keys.ini ← (to be deleted afterward)
- %Application Data%\remcos\logs.dat← (component file)
(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, 7, and 8.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista, 7, and 8.. %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, 7, and 8.)
It drops and executes the following files:
- %User Profile%\Music\regdrv.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista, 7, and 8.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Remcos_Mutex_Inj
- explorer-{Random Characters}
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
Registry Driver = %User Profile%\Videos\Regdriver.exe
Other System Modifications
This Backdoor adds the following registry keys:
HKEY_CURRENT_USER\Software\explorer-{Random Characters}
lic = {Hex Values}
HKEY_CURRENT_USER\Software\explorer-{Random Characters}
exepath = {Hex Values}
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Perform ping
- Enumerate drives
- List all files
- Open file/s
- Get file/s from affected computer
- Upload file/s to affected computer
- Delete file/s from affected computer
- Rename file/s from affected computer
- Create new directory
- Search a file from affected computer
- Download file from url
- Download file from local
- Enumerate process
- Terminate process
- Maximize/Minimize application
- Switch application
- Terminate application
- Open cmd
- Open webpage
- Open screen capture
- Open keylogger
- Set affected computer to send logs automatically
- Deletes cookies and stored browser logins
- Get screenshot
- Capture image from camera if available
- Capture voice from mic if available
- Acquire user password
- Display a messagebox to affected computer
- Sends keyboard input
- Sends mouse click
- Shutdown affected Computer
- Copy clipboard data
- Set clipboard data
- Clear clipboard data
- Manipulate registry entries
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}.{BLOCKED}.30.116
Other Details
This Backdoor does the following:
- This Backdoor gathers the following information and reports it to its servers:
- Computer Name
- System Type
- Product Name
- Primary Adapter
- User Access (Admin or Non-admin)
- User Profile
- User Name
- User Domain
- Processor Revision No.
- Processor Level
- Processor Identifier
- Processor Architecture
- System Type (32-bit or 64-bit)
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
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista, Windows 7, and Windows Server 2008 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
• For Windows 8, Windows 8.1, and Windows Server 2012 users
- Access the Charms bar by moving your mouse pointer to the upper right corner of the screen.
- Move your mouse pointer down and click Settings>Change your PC Settings.
- In the left panel, click General.
- In the right panel, scroll down to the bottom to find the Advanced startup section, then click the Restart now button and wait for the system to restart.
- In the Advanced Startup menu, click Troubleshoot>Advanced Options>Startup Settings>Restart and wait for the system to restart.
- In the Startup Settings menu, press 4 to enable safe mode.
Step 4
Identify and terminate files detected as Backdoor.Win32.REMCOS.TICOGBZ
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- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
To terminate the malware/grayware/spyware process:
- Scan your computer with your Trend Micro product and take note of the name of the malware/grayware/spyware detected.
- Open Windows Task Manager. To do this, press CTRL+SHIFT+ESC.
- View the list of all running programs. To do this:
• For Windows 2000, XP, Server 2003, Vista, 7 and Server 2008 users, click the Processes tab.
• For Windows 8, 8.1 and Server 2012 users, click the Details tab. - In the list of running programs, locate a malware/grayware/spyware file detected earlier.
- Select the detected files, then press either the End Task or the End Process button, depending on the version of Windows you are using.
- Do the same for the remaining detected malware/grayware/spyware files in the list of running programs.
- To check if the malware/grayware/spyware process has been terminated, close Task Manager, and then open it again.
- Close Task Manager.
Step 5
Delete this registry key
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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
- explorer-{Random Characters}
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
To delete registry keys this malware/grayware created:
- Open Registry Editor. To do this:
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter. - In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>Software - Still in the left panel, locate and delete the key:
explorer-{Random Characters} - In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run - Still in the left panel, locate and delete the key:
Registry Driver - Close Registry Editor.
Step 6
Search and delete this file
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There may be some files that are hidden. Please make sure you check the
Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
- %User Temp%\aspr_keys.ini
- %User Profile%\Music\regdrv.exe
- %User Profile%\Videos\Regdriver.exe
- %User Profile%\Music\aspr_keys.ini
- %Application Data%\remcos\logs.dat
To manually delete a malware/grayware file from an affected system:
• For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the File name* input box, type the following:
- %User Temp%\aspr_keys.ini
- %User Profile%\Music\regdrv.exe
- %User Profile%\Videos\Regdriver.exe
- %User Profile%\Music\aspr_keys.ini
- %Application Data%\remcos\logs.dat
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).
• For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:
- Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
- In the Search Computer/This PC input box, type:
- %User Temp%\aspr_keys.ini
- %User Profile%\Music\regdrv.exe
- %User Profile%\Videos\Regdriver.exe
- %User Profile%\Music\aspr_keys.ini
- %Application Data%\remcos\logs.dat
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.REMCOS.TICOGBZ. 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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