BKDR_FARFLI
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted:
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.
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 copies of itself into the affected system:
- %Program Files%\{random folder}\{random filename}.jpg
(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)
It creates the following folders:
- %Program Files%\{random folder}
(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)
It is injected into the following processes running in memory:
- svchost.exe
Autostart Technique
This Backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\{Random Key 1}\
Parameters
ServiceDll = "%Program Files%\{random folder}\{random filename}.jpg"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key 2}\Parameters
ServiceDll = "%Program Files%\{random folder}\{random filename}.jpg"
Other System Modifications
This Backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\{Random Key 1}
HKEY_LOCAL_MACHINE\SOFTWARE\{Random Key 1}\
Parameters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key 2}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key 2}\Parameters
It modifies the following registry key(s)/entry(ies) as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
imgsvc = "StiSvc {random key 2}"
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Download and execute files
- Browses and manages files
- Start/Stop services
- Delete services
- Enumerate running processes
- Create processes
- Get drive information
- Get or change system information
- Perform remote shell
- View desktop
- Creates screen captures
- Record audio and webcam video
- Log keyboard and mouse activities
- Logs the user off
- Manipulate registry
- Get OS Version
- Get Host Name
- Shutdown Computer
- Open/Close a printer - Print a document
- Send stolen information
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- qq87459418.{BLOCKED}2.org
- {BLOCKED}.{BLOCKED}.66.222
- kr.{BLOCKED}i.kr
- {BLOCKED}n900619.f3322.org
Information Theft
This Backdoor gathers the following data:
- OS Version
- Host Name
- System Information
- Drive Information
- Keystrokes
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
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, and then 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_LOCAL_MACHINE\SOFTWARE
- {Random Key 1}
- {Random Key 1}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- {random key 2}
- {random key 2}
Step 4
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
- From: imgsvc = "StiSvc {random key 2}"
To: imgsvc = "StiSvc"
- From: imgsvc = "StiSvc {random key 2}"
Step 5
Search and delete these folders
- %Program Files%\{random folder}
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FARFLI. 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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