BKDR_FYNLOS.RUI
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/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.
It executes commands from a remote malicious user, effectively compromising the affected system.
It deletes the initially executed copy of itself.
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%\azerty.exe - also detected as BKDR_FYNLOS.RUI
(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:
- %User Temp%\svchost.exe - non-malicious file used by this backdoor for code injection
(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 adds the following mutexes to ensure that only one of its copies runs at any one time:
- DC_MUTEX-JDDR2RQ
It injects codes into the following process(es):
- svchost.exe - dropped file
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft\Windows\CurrentVersion\
Run
#nume# = "%Application Data%\#rundll32.exe#"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_CURRENT_USER\Software\DC3_FEXEC
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Lessen system security level
- List disk drives
- List webcams and monitor/capture video
- Change MSN Messenger status & modify contact list
- Shutdown, Restart, Log off or Lock computer
- Empty Recycle Bin
- Visit arbitrary C&C servers
- List active windows
- Remote shell command
- Download and execute files
- Download updated copy of itself
- Upload files
- Log keystrokes
- Refresh or delete logs
- Modify system's host file
- Record and play sounds
- Open and close CD-ROM drive door
- Steal passwords
- Get torrent files
- Refresh Wifi
- Uninstall programs
- Start and control chat sessions
- Monitor activity by Remote Desktop Protocol
- DDOS Flooding
- Manipulate the following:
- • Browser
- • Clipboard
- • Desktop
- • Dialog Box
- • Files
- • Folders
- • Mouse clicks
- • Processes
- • Registries
- • Services
- • Shutdown button options
- • Start button
- • System clock
- • System tray
- • Taskbar
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- skto.{BLOCKED}p.org
Dropping Routine
This backdoor drops the following file(s), which it uses for its keylogging routine:
- %Application Data%\dclogs\{Current Date}-{number}.dc
(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.)
Information Theft
This backdoor gathers the following data:
- Admin rights
- Computer/User name
- Language/Country
- Operating System information
- Network configuration
- Screen Resolution
Other Details
This backdoor deletes the initially executed copy of itself
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\Microsoft\Windows\CurrentVersion\Run
- #nume# = "%Application Data%\#rundll32.exe#"
- #nume# = "%Application Data%\#rundll32.exe#"
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
- DC3_FEXEC
- DC3_FEXEC
Step 5
Search and delete this file
- %Application Data%\dclogs\{Current Date}-{number}.dc
- %User Temp%\svchost.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FYNLOS.RUI. 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
Scan your computer with your Trend Micro product to delete files detected as BKDR_FYNLOS.RUI. 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.