BKDR_FARFLI.XXZF
Win32/Farfli.BGG (ESET-NOD32)
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 deletes itself after execution.
TECHNICAL DETAILS
536,576 bytes
EXE
No
10 May 2017
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%\Windows NT\winlogin.exe
(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.)
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\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
ImagePath = "%Program Files%\Windows NT\winlogin.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
DisplayName = "Microsoft .NET Framework NGEN v2.0.5273"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
Description = "Microsoft .NET Framework NGEN"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
ConnectGroup = "ĬÈÏ·Ö×é"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
ErrorControl = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
MarkTime = {Date of malware execution}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
ObjectName = LocalSystem
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
Type = "272"
It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Microsoft .NET3
Other Details
This Backdoor connects to the following possibly malicious URL:
- http://users.{BLOCKED}e.qq.com/fcg-bin/cgi_get_portrait.fcg?uins=450318992
- {BLOCKED}9.110.67
- {BLOCKED}30.86
- {BLOCKED}3.210.212
It deletes itself after execution.
SOLUTION
9.850
13.398.04
11 May 2017
13.399.00
12 May 2017
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 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\SYSTEM\CurrentControlSet\ Services
- Microsoft .NET3
- Microsoft .NET3
Step 4
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FARFLI.XXZF. 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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