Backdoor.Win32.REMCOS.USMANEAGBW
Trojan.MSIL.Krypt (IKARUS); Win32:Trojan-gen (AVAST)
Windows
![](/vinfo/imgFiles/legend.jpg)
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.
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 adds the following folders:
- %Application Data%\remcos\
(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It drops the following copies of itself into the affected system:
- %Application Data%\remcos\remcos.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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It drops the following files:
- %User Temp%\install.vbs - execute the dropped malware copy
- %Application Data%\remcos\logs.dat - record of user activity\keystrokes
(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following processes:
- %Program Files%\Internet Explorer\iexplore.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Remcos-6PE8QV
- Remcos_Mutex_Inj
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
remcos = "%Application Data%\remcos\remcos.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe, %Application Data%\remcos\remcos.exe"
Other System Modifications
This Backdoor adds the following registry entries:
HKEY_CURRENT_USER\Software\Remcos-{random}
exepath = "{hex values}"
HKEY_CURRENT_USER\Software\Remcos-{random}
licence = "{random}"
HKEY_CURRENT_USER\Software\Remcos-{random}
Inj = 1
Backdoor Routine
This Backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}.{BLOCKED}.153.18
Information Theft
This Backdoor gathers the following data:
- Computer name
- Username
- User profile
- User domain
- Home Drive
- Logon Server
- Processor Architecture
- Windows Version
- System Type (x64, x86)
- User access (if admin or not)
- Computer Memory Information (RAM, Virtual memory)
Other Details
Based on analysis of the codes, it has the following capabilities:
- Copy Directory
- Delete Directory
- Create Directory
- Move Directory
- Get Directory Information
- Get Drive Information\Status
- Get Mapped Drives
- Delete Mapped Drives
- Add Mapped Drives
- Dummy Speed Test
- Execute a command
- Run a process
- Change File Directory
- Copy File
- Link Files (Hard Link)
- Create Shortcut
- Delete File
- Check File Existence
- Enumerate Files
- Get File Attributes (Size, shortname, longname)
- Get File Location
- Delete File
- Empty Recycle Bin
- Modify File
- Install File
- Open File
- Read File
- Modify .ini files
- Activate Keylogger
- Perform Ping
- Display Messagebox
- Get Running Processes
- Terminate a Process
- Check if a process is running
- Delete Registry Key\Entry
- Enumerate Registry Key\Entry
- Modify\Add Registry Entry
- Upload Files
- Download Files
- Shutdown Affected Machine
- Put Machine to Sleep
- Play Sound
- Get active window
- Close a window
- Check if Window is open
- List windows
- Minimize windows
- Set window on top
- Move Window
- Wait for a window to be active
- Check user cookies and cache
- Clear Cookies and Cache
- Run the Command Prompt (CMD)
- Flash a window
- Obtain user Logs
- Capture Image
- Capture Audio
- Open web browser
- Send keyboard input
- Send mouse clicks
- Disable mouse\keyboard inputs
- Write text to clipboard
- Receive text from clipboard
- Clear clipboard data
- Check for CD drives
- Acquire User Passwords and Login Data
SOLUTION
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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 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
- remcos = "%Application Data%\remcos\remcos.exe"
- remcos = "%Application Data%\remcos\remcos.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- Userinit = "%System%\userinit.exe, %Application Data%\remcos\remcos.exe"
- Userinit = "%System%\userinit.exe, %Application Data%\remcos\remcos.exe"
- In HKEY_CURRENT_USER\Software\Remcos-{random}
- exepath = "{hex values}"
- exepath = "{hex values}"
- In HKEY_CURRENT_USER\Software\Remcos-{random}
- licence = "{random}"
- licence = "{random}"
- In HKEY_CURRENT_USER\Software\Remcos-{random}
- Inj = 1
- Inj = 1
Step 5
Search and delete these files
- %Application Data%\remcos\remcos.exe
- %Application Data%\remcos\logs.dat
- %User Temp%\install.vbs
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.REMCOS.USMANEAGBW. 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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